# embeddings_queue

created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090736-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "YouTube channel and join our Facebook page Arab Oil and Gas Academy for our latest updates on our upcoming courses. Please feel free to send your questions in the chat box and we will answer as many questions as possible. With that I ask you to give your full attention to Dr. Mohamed Suleiman and help me in welcoming today's very honorable guest. Please welcome Dr. Mohamed Solomon. Hi, Dr. Solomon. Thanks for joining us today. We're so glad to have you on Pipe Petro. Thank you very much for the kind introduction. Welcome, everyone. My name is Mohamed Solomon. As was mentioned, I want to talk to you today and for three more lectures in October, about Hydraulic Fracturing. It is ... the course is, is an introductory course, ... so we don't go into a lot of details, but we do have in University of Houston, obviously, courses that we, we teach in more details in Hydraulic Fracturing. I personally taught both undergraduate classes, as well as very the involved graduate course. Here we're"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "in more details in Hydraulic Fracturing. I personally taught both undergraduate classes, as well as very the involved graduate course. Here we're just giving you an... an outline of Hydraulic fracturing. Maybe in the future we go in some specific areas of hydraulic fracturing. Basically I'm going to cover four lectures, about an hour, hour and 15 minutes each. The first one will be, which is today, we'll talk about the history of fracturing, and I'm going to also talk about fluid flow aspects when you have a hydraulic fracture intersecting the water. Next lecture will be talking about in-situ stresses, then we'll talk about fracture design, and then we'll talk about this thing. There is a lot more that one can discuss later on. ... A lot of material that you are going to see in ... in today, and also in the... later in, in the course, in those lectures, are taken out of these two books. The history, if you want to learn more about the history of hydraulic fracturing, we wrote a very"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "those lectures, are taken out of these two books. The history, if you want to learn more about the history of hydraulic fracturing, we wrote a very interesting chapter in that second book, Optimization of Hydraulic Fraction Stages, Sequencing in Unconventional Formations. The rest of the chapters, the rest of the lectures, you're going to find a lot in, in fractional and horizontal well, ... wells. I also plan to, to post those ... a PDF copy of those lectures on, on, online for you to, to see, and you can download. Basically on Researcher Gates, and if you get on Researcher Gates, type my name, you're going to find a lot of material. I will be putting the... those lectures one by one on ... on Research Gates. So, let us talk first about ... history of fracturing. First, the first thing you wanna learn is, what is the basic principles behind the hydraulic fracturing? All you are doing, and we'll ... we'll look at equations later on, hopefully we'll have time to do that. You are"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "behind the hydraulic fracturing? All you are doing, and we'll ... we'll look at equations later on, hopefully we'll have time to do that. You are injecting fraction fluid at high enough rate, that the formation cannot take all that fluid. And so what is happening is the wellbore itself balloons a little bit, it gets a little bigger and the formation breaks down. It breaks down under tension. It is similar, in a way, if you blow into a balloon it gets bigger and eventually it pops, it breaks. This is the same thing what's happening inside the well. It balloons, it gets a little bigger, and we have done a lot of experiments, both in the lab, as well as in the field, where we could see that. The well balloons a little bit, and then it breaks in tension, and we're going to talk about, when we get about, talk about stresses, we'll see how this happens. Once it breaks, you are forming a hydraulic fracture. Hydraulic fracture is because as the word mean is you have liquid going in and now is"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "happens. Once it breaks, you are forming a hydraulic fracture. Hydraulic fracture is because as the word mean is you have liquid going in and now is usually liquid is water-based as an aqueous phase. Once you propagate the fracture eventually you're going to stop the fracture or close again in order to keep it open. You want to, during the injection process, you want to put something in there that keeps the fracture open after the fluid all leaks off. And that something is your proponent. People used to use all kinds of things before, including walnut shells, if you go back to the 40s and late 40s and early 50s, they used to say walnut shells. Now, then we talk about sand, actual natural sand, then you use artificial propant, and these days use all kind of things and as we're going to discuss later it depends on the formation how deep it is how what stresses and so on and so forth we'll get into that the important thing for us to know now is you're using propant to keep these"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "deep it is how what stresses and so on and so forth we'll get into that the important thing for us to know now is you're using propant to keep these fractures open and we're going to see why we want to keep it open when we get into the fluid flow part of it later this morning. So let us talk a little bit, let us talk a little bit about the birth of the process. The idea of hydraulic fracturing, ... came up several years ago, almost 70 plus years ago. And it was conceived by a gentleman called Floyd Farris. It was a small oil company, that later on became Amaco. I... you probably don't even recognize the name, small oil company, that later on became Amaco. I, you probably don't even recognize the name, because Amaco was taken over by, by BP many years ago. Maybe not, when I talk about many, many years ago, I believe it was in sometimes in the 90s. So it is still, it is still 20 plus years ago. The first job was successful, at least mechanically. They fractured the weld, they created"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090b0a-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "in the 90s. So it is still, it is still 20 plus years ago. The first job was successful, at least mechanically. They fractured the weld, they created the fracture that they wanted, however there was no production whatsoever. One of the problems they had is in order to carry sand or propant you need to, and in order for the fluid not to leak off into the formation, you want to make it a little thicker, a little higher viscosity, so you gel the fluid. But you, at the end of the job, you need to break that gel again, otherwise it will damage the formation. So these days, at the time, let me go back, at the time, the ferrite job, they did not have a gel breaker included in the fluid. And so what happened, you have no gel breaker, so there's no production, it's damaged well. So obviously, jobs after that, they added the gel breaker, very much like what we do right now, where it start acting, it has delayed reaction. So delayed reaction, very much like when you, one takes a Tylenol and it"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090ba0-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "like what we do right now, where it start acting, it has delayed reaction. So delayed reaction, very much like when you, one takes a Tylenol and it releases slowly with time. This is very similar thing. Now you have the breakers released slowly with time, it breaks the gel at the end of the job and you can clean it up, it will be no problem. So that the second and third job worked very well. And, the company, Stan Lloyd Oil and Gas Company, got a patent back in 1948. That's probably one of the most valuable patent any company had got. So, 1948 was a very good year. There was some experiments, let's talk about some of the experiments that happened before. Early on, they were not using, some of the cases were not using water, they used napalm. Napalm is a very nasty fluid, basically it is gel decrucine and gasoline. So you can see it can catch a fire. It actually, napalm was used before and after that time in wars. And so if you can Google napalm, you're going to find out where it was"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090c36-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "catch a fire. It actually, napalm was used before and after that time in wars. And so if you can Google napalm, you're going to find out where it was used. It actually caused a fire in one of the early jobs and the inventor of hydraulic fracturing died in that fire. So it is after that people obviously started shying away from using fluids like that. We'll talk about fluids in a minute. Okay, the revenue from that patent that was issued was actually is the contributed very much to construction of Amaco production research lab in Tulsa, Oklahoma, which has been given to one of the universities now since Amaco moved out or was taken over by BP. So let us talk about how it progressed. So, you started the first job, it was in Hugerton, the first job was in Hugerton Field in Kansas, United States. By late 1948, ... we... there was 23 wells that were fractured, so it was very successful. No other patent was applied as fast and as high impact as the patent on hydraulic fracturing. At the"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "that were fractured, so it was very successful. No other patent was applied as fast and as high impact as the patent on hydraulic fracturing. At the time, they called it HydroFrac. And in 1949, a company, a service company called the Hauko got exclusive license for that hydrofrag process. Hauko is actually a Haliburton company. It is, as you can see, it is a Haliburton oil well cementing company. Haliburton company started as a cementing ... company and then ... it got the license for hydraulic fracturing, so it became mostly a hydraulic fracturing company. I'm not talking about it, by the way, just for your information, I worked for almost 32 years for Haliburton company, before going to Universities ... about 10 years ago, actually almost exactly 10 years ago. The commercial application increased very quickly, you have 322 wells that were fractured in one year, success rate was very high. Even offshore application were applied. The first company that did the offshore fracturing was"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090d6c-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "fractured in one year, success rate was very high. Even offshore application were applied. The first company that did the offshore fracturing was Kermagui. It doesn't exist anymore. It was taken over by Anadarko and Anadarko was also taken over by another company. So as you can see, there is a lot of consolidation in the industry. It was offshore, although it's only 18 feet of water, but it is still, it was 12 miles offshore. And now we drill and we fracture wells that are thousands of feet underwater. By 53, we had 20,000 jobs. Other companies were licensed to perform hydrofrack, you can see Slumber J, Liberty, Baker Hughes and all those companies came in, and by mid 50s were the high rate waterfracks and large jobs. The, one interesting evolution is, initially people thought that hydraulic fractures are horizontal, basically along the bidding planes. Till there is a paper by Hubert and Willis, in 56 that talked about the fraction should be vertical, unless you are in a very shallow"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090e02-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "bidding planes. Till there is a paper by Hubert and Willis, in 56 that talked about the fraction should be vertical, unless you are in a very shallow situation. Most of our applications are deeper than 1500 feet or so, they are vertical fractions. We are going to actually look at the equation from Hubert and Willis paper, is a extremely important paper that affected the development of hydraulic fracturing. Another paper that was very influential too, was one by Anderson and Stahl, 1967. He basically looked at hydraulic fracturing in the field and at the time there was a start of running experimental experiments in the lab, in rock mechanics labs, and it did confirm that fractures are indeed usually vertical. Does not mean you are not going to see horizontal fractures. They are fairly rare and under certain conditions. usually vertical. Does not mean you are not going to see horizontal fractures. They are fairly rare and under certain condition. We'll get into it very little later on."}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090ea2-8640-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "not mean you are not going to see horizontal fractures. They are fairly rare and under certain condition. We'll get into it very little later on. But majority of your fractures will be vertical. We'll talk about when we get in stresses next week, we'll talk more about this issue. Let me show you a couple of pictures so you see what is, how it used to be done. You see this is very early frack and you can see they were just dumping sand by hand and I can tell you from personal experience that this is usually a very bad idea. Now we don't do that, now everything is mixed properly in a blender. I had to run an experiment, a field experiment actually, not exactly, it was not exactly a field, but without going into detail, it was an experiment that we're using an actual fracturing truck. So we're injecting at fairly high rate, about one barret per minute. So for a short time, we were looking at specific effect without, I don't want to go into that specific research, but when we try to do it"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090f42-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "per minute. So for a short time, we were looking at specific effect without, I don't want to go into that specific research, but when we try to do it by hand, things did not really work well, because you can't keep constant sand concentration. So, this is probably one reason they were having some cases that were successful, and some that were not. By the way the experiment that I ran I've never written a paper on that, there was reasons for that, but they were very successful I can tell you. Historical based fluid trends, you can see that although it started with oil-based fluid, quickly people moved into water-based fluid, so it became the dominant application. And also, back in the late 70s and 80s, people started getting into using foam. Foam is a very, very good carrier of problems. However foam does not give you, since it's mostly air, it does not give you a larger hydrostatic head. So it works very well in shallower formations, formation that does not have very high pressure. If"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26090fec-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "it does not give you a larger hydrostatic head. So it works very well in shallower formations, formation that does not have very high pressure. If you have high pressure formation, you have deformation, foam may not be exactly the best option. People shy away from oil-based fluid because of potential danger, you know. Although there was some recent, fairly recent work where propane was used, but many major service companies shied away from it. Actually the patent for that fluid was done, if I remember correctly, by a Halliburton company and they sold the patent because they did not want to be involved in potential risk. In the 60s, now people knew that fractures are mostly vertical, thus we have more viscous gel defluid and became a very high problem to concentration in late 70s. When I say high problem concentration, I remember some of the cases we were involved in were all in excess of six pounds per gallon. Some of them were going to 12, 14 and 16 pounds per gallon. That's very"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "of the cases we were involved in were all in excess of six pounds per gallon. Some of them were going to 12, 14 and 16 pounds per gallon. That's very high, that's... you don't do that anymore. You do it only if you have a very high probability formation. And, we're going to talk a little about fracturing high probability formation. So, things will to work well and people started looking at stimulation by using, having a computer van on the job collecting information. Pressure, rate, analysis of fluid to get the N prime and K prime the properties of the fluid. Okay, so this is basic summary of how the fluid, fraction fluid went on. If I'm talking too fast, please, you know, let me know. But you can listen to it again. Then there was a the increase in oil price really did change things. So let us look at at prices and this price is if you look at it and looks a little different is because we took all the prices to 2015 base and so if so if you look at the prices in 60 and 70, they were"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "look at it and looks a little different is because we took all the prices to 2015 base and so if so if you look at the prices in 60 and 70, they were two or three dollars per barrel. But when you take it to 2015, it was close to $2015. It would be close to $20. And you can see back in 73, there was a sharp jump in price of oil. If I'm sure most of you are too young to remember or to even know, unless you read history books. That's when there was a war between Israel and its neighboring countries, the Arab countries, and it was an oil embargo. And oil prices went up and it was very difficult to go back to that original price. And that's actually when it goes up to $60 per, the oil goes up to $60 per barrel, or 50 goes to 60. That means that you want to, you can spend more money to bring in that oil, and that actually affected fracturing. So, started in the late 70's, in mid, mid to late 70's, there was a lot of effort done into fracturing, a lot of technology been developed. I was"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "So, started in the late 70's, in mid, mid to late 70's, there was a lot of effort done into fracturing, a lot of technology been developed. I was lucky, I actually got my PhD in 78, and you can see in 78, 79 prices were going up, companies were hiring, activities were just unbelievable. In 1980, 1981, the price of oil was equivalent to $100, with today's dollars. But, in mid-80s, there was a sharp decline in price. 86 was a crash in, in the whole business, ... different from what we see right now, but still there was a crash in, in prices, and that of course affected, affected level of activities. The prices stayed a kind of low for some time and it picked up again in years, in about 2000s. I will get into that in a bit. You're going to see that graph again. Right now I just want to focus on that early part. So, in mid-80s we had the very first crash and the recount went down from over 4,500 down to, I'm talking about in the United States. Internationally they had 1,700 went down to"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "first crash and the recount went down from over 4,500 down to, I'm talking about in the United States. Internationally they had 1,700 went down to 800, so it was not as bad. Fracturing, however, was more concentrated in the United States, although we were involved in fracturing even at the time. There was some in South America, I was involved very much in that, some in Brazil, some in Canada, very much in that, some in Brazil, some in Canada, but was focused mostly in the western hemisphere. There was not a whole lot in the eastern hemisphere. And at the time, there was companies starting to do downsizing and they called it right-, there was salary freeze, there was furlough. I remember working several weeks, six weeks and then take a week off without pay, that was a common thing to save jobs for everybody. And then we got, when we in the late 80s, although some people think it is very recent, in the late 80s we although some people think it is very recent, in the late 80s we got into"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "late 80s, although some people think it is very recent, in the late 80s we although some people think it is very recent, in the late 80s we got into fracturing horizontal wells. Actually the first project was a research project. I was personally, I was involved in that project. I was in, we looked at a well, actually a small oil company came up with the idea, they contacted Halliburton company, Halliburton formed a team, we were looking, some people were looking at logs, some people were looking at cementing. I was involved in it from the rock mechanics, fluid flow and refraction site. Actually I wrote a paper on the subject. We presented it in 1988. It was published in Holland, not in Holland, in JPT, Journal of Petroleum Technology, back in 1990. So that's 30 years ago. And if you read it, you're going to see some of the stuff that we still talk about. It's so amazing, the things just to go in. Except we were looking at fracturing wells, horizontal wells, but we're looking at"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "we still talk about. It's so amazing, the things just to go in. Except we were looking at fracturing wells, horizontal wells, but we're looking at creating four to six fractures per well. First, the horizontal wells were not very long, and the number of fractures, because we had to create every fracture independently, and so, we did not create a huge number of fractures. We fractured the wells here, in the late 80's we fractured wells in Canada, of course in United States first, we fractured wells in United States, in Canada, South America, and we had a very interesting project in Europe, in Germany, where we fractured one well. I actually, I was involved in that. I ended traveling. I found about it the day before the meeting. I had to fly to Germany. We had our meeting. We talked about how to design it, what to do. And we flew back. It was an interesting trip. interesting trip. And then we got into, eventually, we fractured the, we fractured chalk. That was very interesting. We got"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "was an interesting trip. interesting trip. And then we got into, eventually, we fractured the, we fractured chalk. That was very interesting. We got into fracturing Austin chalk. It was very interesting. We got into fracturing Austin Chalk, it was very successful. However, it was hit and miss sometimes because if you don't intersect natural fractures in the chalk, it is not very successful. Then a small company in the Bernet shield wanted to try fracturing Mitchell energy, I should say. Mitchell energy wanted to try fracturing horizontal wells in shale. And boom, it worked very, very well. So, wells that were not very productive all of a sudden, they were extremely productive. productive all of a sudden, they were extremely productive. And so that is started the increase in Shale, or the Shale revolution as people call it. The Barnett Shale works very well for reasons we can discuss later on. Barnet shield works very well for reasons we can discuss later on. So as we started working"}


created_at: 2023-11-18 18:31:57
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "works very well for reasons we can discuss later on. Barnet shield works very well for reasons we can discuss later on. So as we started working with other shields we wanted to do something to make those shields similar to the Barnet shield. We can discuss that later on. Although it is more of a research area, but it's very interesting to talk about. And so, the reason you look at the 2000s now, prices are going higher and increases, and now you end the fracturing shale, and as you fracture shale, you're producing more oil and more gas and that affects the price of ... of oil and gas, so it ends going down. So you, you... industry is really successful in doing things but in a, in a way it hurts, it hurts a little, because it reduces price. So that, you can see recently the prices were going up to $100 per barrel of oil, and then boom suddenly it declines, because you, there's a lot of shale in, in the world and not only the Western Hemisphere was fracturing, but also the Eastern"}


created_at: 2023-11-18 18:31:57
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "suddenly it declines, because you, there's a lot of shale in, in the world and not only the Western Hemisphere was fracturing, but also the Eastern Hemisphere. So, we... most people think of ... of fracturing as only for low permeability reservoirs. That is... that is in a way true, but is also not exactly true. ... We, we fractured low probability reservoirs, we get into fraction share, we'll talk about that in next two, next few weeks as we work. But it, we have also fractured the high probability formation. We, we are not going to get much in that, but if you're interested, there are a bunch of papers, we wrote a paper on the subject back in 1993-94, we brought a couple of papers on that subject. It's a very important subject by the way, because we have been fracturing our formation in the Gulf of Mexico, the formation that have not one or two millidarcy and we talk about low permittivity reservoirs like in shale that is nano-darcy, macro-darcy and nano-darcy, but in the Gulf we"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "one or two millidarcy and we talk about low permittivity reservoirs like in shale that is nano-darcy, macro-darcy and nano-darcy, but in the Gulf we fractured the formation that is can be 10, 20, 50, middle of the Darcy formation, but under special condition that we are not going to be discussing right now. But those formation have been fractured and we've been analyzing the data. We'll get, when we get in the analysis I will show you an example of, of fracturing hyper formation. of fracturing hyper-information. So, basically, when you do that, it's originally was, was looked at as sound production control, but is actually a fracturing process. Fracturing implementation is very complex. You need knowledge, not only fluid flow, many of petroleum engineers, they end up getting trained only in fluid flow, but this is more than just a fluid flow. It is fluid flow, it is fracture mechanics, it is rock mechanics, it's some operation you need to look at prop and... So, there is a lot of"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "flow. It is fluid flow, it is fracture mechanics, it is rock mechanics, it's some operation you need to look at prop and... So, there is a lot of things one has to, has to learn in order to be an expert in, in that area. And, it is fairly expensive there fairly expensive for a company to apply. This is the one reason you have specialized service companies that do the fracturing. Let's talk about this a little bit because this is also related to something that I've given lecture on to... to students some time ago, and you are going to see it also on YouTube. The Hydraulic Fraction, different between Hydraulic Fraction and the other Fracturing techniques. Because, one can say, Hey, I can fracture using something a little different, I can use explosive or propellant, I'll talk about both of that. And actually in... I did not talk about, I did not mention in history of hydraulic or fracturing. About... so at one time people used the... or it was an experiment, to use nuclear bomb. And"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "I did not mention in history of hydraulic or fracturing. About... so at one time people used the... or it was an experiment, to use nuclear bomb. And it's actually was applied, and as you can see is a really bad idea but people have tried explosives and explosives is a bomb basically and the pressure goes up very fast so in a microsecond you reach many thousands, maybe a million PSI. And so, it is very damaging to the formation, it's basically solid rocket fuel. It burns, it burns very quickly, it reaches very high pressure, but it's uncontrolled. In milliseconds, you can reach very high pressure, so indicating multiple fractures. Explosives will do even, even more of that, it creates cracks all over. And then we have the plasma stimulation, that's what I discussed in waterless fracturing, sometime ago you'll find it in YouTube, you may, maybe you want to look at it sometime if you're interested. We also reach a very, in a few microsecond, we reach high pressure, but not as high as"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "maybe you want to look at it sometime if you're interested. We also reach a very, in a few microsecond, we reach high pressure, but not as high as what you see in propellant or explosives. You end up having multiple fraction, but it is more controlled process than you see in propellant, as well as repeatable. In hydraulic fracturing, now you reach that maximum pressure which is fairly low relative to the, to this other three approaches, but it takes many seconds or even minutes. So it is, although everybody will talk about it as a dynamic process, but when you look at what properties we use in Hydraulic Fracturing, we use the static properties of, the static mechanical properties of the rock, because it is fairly, relatively slow, you're not vibrating the grains, you are cracking the rock, relatively slow, relatively slow compared to explosive propellant or plasma. Those take microseconds, hydraulic fracturing takes many seconds or even minutes. So this is basically a representation"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "propellant or plasma. Those take microseconds, hydraulic fracturing takes many seconds or even minutes. So this is basically a representation of what happens. You can see explosives create cracks in every direction. And it may not be as effective when we get into the fluid flow. Actually, long hydraulic fracturing is definitely more effective than having an explosive that crushes the rock and it can make the rock somehow glassy. ... Multiple propellant, the rise time is fairly fast and it can create multiple fracts. There's other applications along that people have used, propellant as well as propellant as well as having high pressure Nitrogen to follow up, to follow in the, that fracturing of, of the well. And so there was a lot of applications on, in this approach back in, in the mid 80's and early 90s. It's not used as much as we look at. Then hydraulic fraction has been always very, very successful. When you look at the fluid flow, we'll get a, we'll show you a comparison between"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "at. Then hydraulic fraction has been always very, very successful. When you look at the fluid flow, we'll get a, we'll show you a comparison between hydraulic fractions, how it changes production. And you can quickly will see a relative comparison with other applications. So let me look at the fluid flow. So hydraulic fracturing is a tensile failure. Just to remind you, if you have not studied that, ... if you, if you look at a rock, any rock, like sandstone, is very strong in compression. If you get a rock and you test it under compression, it takes very high pressure, even without surrounding the rock with stress. So, if you have unconfined compressive strength of the rock, unconfined meaning that, the sample you are, you're putting under compression, does not have any stresses on it sideways. The rock, the unconfined compressive strength of sandstone is in neighborhood of 4,500 to 5,000 PSI. So it's fairly strong and now if you apply confining stress, it increases very quickly. We"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "of sandstone is in neighborhood of 4,500 to 5,000 PSI. So it's fairly strong and now if you apply confining stress, it increases very quickly. We are not going to talk much more about it than that, at least right now, but in tension rocks are very weak. The tensile strength of sandstone for example would be between 100 to 200 PSI. You see, you can see that comparison between 5,000 PSI and a couple of hundred PSI. So, ... so fractures ... in, in rocks will, is a, is a tensile failure, not a compressive failure, although sometimes people think it is, you're compressing the rock, it's, it's compressive failure, but actually you need to look at the tip of the fracture, it is breaking under tension. This is one reason many times, sometimes in equations, people may ignore that, the tensile strength of the rock. Okay. How does it work? You know, if I ask you why fracture works and you tell me that because you change probability of deformation, you would flunk this course. The fractures, it"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "if I ask you why fracture works and you tell me that because you change probability of deformation, you would flunk this course. The fractures, it may change the permeability just around the fracture phase. But, fractures work not because they change permeability, but because they modify the flow pattern inside the reservoir. So, if I'm looking at a droplet of oil, instead of this droplet moving to the wheel bore taking a long path, I don't know whether you see my... So if I have droplet of oil here, rather than, than moving to, sorry, rather than moving to the wheel bore, it moves first to the hydraulic fraction and then this hydraulic fraction has very high permeability. The formation may be micro-Darcy or a fraction of mainly Darcy, but the permeability inside that fraction may be in Darcy's. Actually, depending on the type of fraction, it may be going from 10 Darcy to 100 Darcy. So, the pattern of fluid flow changes, is no longer, no longer radial flow. You know, you study these"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "it may be going from 10 Darcy to 100 Darcy. So, the pattern of fluid flow changes, is no longer, no longer radial flow. You know, you study these equations, Darcy equation, most people will set Darcy equation and talk about radial flow. Here is not radial flow, it's a lot more complex than, than radial flow. We'll, we'll talk about the different type of radial flow, of flow inside reservoir in, in a second. So when I look at the hydraulic fractured weld, I would say, well, one wing of the fracture is, length is LF, and most of the time people will assume that the hydraulic fracture has symmetry. So both lengths are the same. Are they exactly the same? Probably not, but it's unless the difference is huge, which usually is not the case, you can't tell the difference. You can approximate it with symmetric fractures. So you're saying I have length of LF, I have fracture width of W, and W, this fracture width may, after the fracture closes, it may be 0.2 inch. 0.2 inch is about five"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "have length of LF, I have fracture width of W, and W, this fracture width may, after the fracture closes, it may be 0.2 inch. 0.2 inch is about five millimeters. I tended to use English units, that's what we use in the field. So it's about 0.2 inch and when a fracture hyperventilates formation we do special things and we end up having maybe a wider frac, maybe going to half an inch or even up to three quarters of an inch. So that's a very wide frac. So, what would be the probability of a smooth surface open crack? If it's the width on the, it's 0.01 inch, not even 0.2 inch. And the probability if it is open and the surface is smooth, so I have two, basically like a wedge here, the probability would be 54 times 10 to the power 9 w squared. So you can see the probability would be extremely, extremely high. However, realistically speaking, because the fracture is not as smooth, it has propent inside, there may be some damage around the fracture, you can realistic fracture probability is"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "because the fracture is not as smooth, it has propent inside, there may be some damage around the fracture, you can realistic fracture probability is can be go from anywhere from 1 to 200 Darcy. You get this equation just for a few, wanna find out how did I get this equation? This equation you get by equating Poiseuille's equation for open crack to Darcy equation. And so in most of our work when we talk about from now on, I'm going to assume is simple FRAC. We'll work with simple FRAC where one wing is LF. So when I say fracture length, actually I'm talking about one wing of the fracture. So when people talk about LF, they talk about one wing of the fracture. So when people talk about LAF, they talk about one wing of the fracture. And I'm going to say my original formation probability is K, formation probability is, fracture probability is KF, and which of the fracture is W, or WF. Okay. W, or WF. Okay? And I'm going to assume I'm penetrating the whole formation, so it have height H,"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "is KF, and which of the fracture is W, or WF. Okay. W, or WF. Okay? And I'm going to assume I'm penetrating the whole formation, so it have height H, the P zone is have the same height. Obviously you can deviate from those conditions but that's not for this class here, we're looking at basic behavior. If you've studied petroleum engineering, you know some of those parameters, so let me say, let me look at the changes in those dimensionless parameters. So I'm assuming you already know what dimensionless pressure is for case of oil, liquid, case of gas, or in case of liquid here it is, in case of gas here it is. And if this one, this would be dimensionless rate, 1 over dimensionless rate. In case of when I deal with hydraulic fracture, now dimensionless time, when I have radial flow, we have this terms everything the same except I have Rw squared. In case of fracture, we replace the Rw with length of one wing of the fracture, so LF square. Now there is one parameter you need to remember"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "In case of fracture, we replace the Rw with length of one wing of the fracture, so LF square. Now there is one parameter you need to remember always, which is dimensionless fracture conductivity, that's an important parameter, it's actually, it relates the fracture effectiveness basically to formation. So you have Kfw, this is your fracture width, fracture width and fracture permeability, divided by formation permeability and one length of the fracture, one wing of the fracture. So safety is very important parameters to remember. And some of the literature, they are going to call it F-sub-CD. Some people still use that F-sub-CD, it is the same thing. So FCD or CFD, SPE likes to use CFD right now. Kfw divided by KlF, you have to remember that. Some of the dimensions parameters, you know, if you are my student taking my class, I would expect you to know those definitions by heart. You can't always Google things. So let us talk about what kind of hydraulic fracture we have. I'm going to"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "you to know those definitions by heart. You can't always Google things. So let us talk about what kind of hydraulic fracture we have. I'm going to talk about only two types. One is infinitely conductive fracture, so infinite conductivity fractures versus finite conductivity fractures. First is there anything as infinite conductivity fractures? The answer to this is no. There is nothing like infinite conductivity. However, it behaves, the system will behave as if it has such a high conductivity that for all practical purposes it is infinite. Let us say this in a different way. Basically, in infinite conductivity fracture, what we are saying is that the pressure drop inside the fracture is so small relative to the pressure drop inside the reservoir that I can ignore it, ignore the pressure drop inside the fracture. So if my pressure drop inside the fracture is one psi, and the pressure drop inside the formation is 500 psi, or a thousand psi, and then you're talking about way smaller"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "inside the fracture is one psi, and the pressure drop inside the formation is 500 psi, or a thousand psi, and then you're talking about way smaller than 1%. So I can assume that as if there is no pressure drop inside the fracture. So many and many high conductivity fractures that you will see that behavior. Finite conductivity fracture basically what I'm saying is the conductivity, the pressure drop inside the fracture is significant relative to the pressure drop inside the formation. It's not higher, it's still a lot smaller than the pressure drop inside the formation, but the value cannot be ignored. Okay, let's look at CFD. If CFD is higher than 300, then you can assume that the fracture is infinitely conductive. That value, you know, if you read all the literature, it may be 500, some recent literature, they may even look down to 100, and say this is an infinite conductivity fracture. However, many of those fractures would behave as a finite conductivity fracture. So anything less"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "and say this is an infinite conductivity fracture. However, many of those fractures would behave as a finite conductivity fracture. So anything less than 300, at least from theoretical point of view, will behave like finite conductivity fractures. So let's look at, this graph was published, this is the behavior of infinitely conductive fracture was published by Remy and some of his students. There's more than one student who worked with him on that. Remy was, Professor Remy was professor in Stanford University. And I had the privilege actually of taking classes with him. Was a great professor in all aspects, as a researcher, as a person, great man. He passed away many years ago. he passed away many years ago. And so that work is showing dimensionless pressure versus dimensionless time based on, for a fracture. So it has LF squared, and it shows something very interesting. It shows that the early time is a straight line with slope of one half, then you have curvature, and that"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "and it shows something very interesting. It shows that the early time is a straight line with slope of one half, then you have curvature, and that curvature continue like this. Then it eventually, at about time of five, it behaves very much like radial flow. So the early time is slope of one half then the curvature that we can't really easily analyze and then about dimensionless time of five or if you if you're not very strict you can say three it the fracture behaves like radial flow as if there is no fracture and then if it sees a boundary later on, then the boundary effect will appear slow one to one. Okay. So let us look at this behavior. So the early time, slope of one half, basically if you take the logarithm of this equation, it gives you, it says that log of pressure, dimensionless pressure, or delta P, versus log of time, it gives you a slope of one half. And this equation basically is equation indicating linear flow. Anytime you see a square root of time behavior like this,"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "you a slope of one half. And this equation basically is equation indicating linear flow. Anytime you see a square root of time behavior like this, usually this is linear flow. Anytime you see a square root of time behavior like this, usually this is linear flow. So early on, you have linear flow. Later on, after dimensionless time of five or three, if you're not too strict, if you're not too strict, you have behavior of dimensionless pressure is function of natural log of time. Does this equation remind you of anything? This, the first part at least, is what you see in radial flow. If you look at radial flow equation without any fracture, it is PD equal to one half of natural log of TD plus skin factor. So very early on is linear flow. After long time is it behaves like radial flow. long time is it behaves like radial flow. So that's assumption here is you can reach that radial flow. Dimensionless time of five since it has LF square in it can take long long time. In classes that I"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "assumption here is you can reach that radial flow. Dimensionless time of five since it has LF square in it can take long long time. In classes that I teach, I get the students to calculate the time, say for a tide gas formation to reach that dimensionless of time of five or even three and you find out that it may be many many many years. You know, it's not uncommon to calculate 10, 15, 20 years, depending on the properties of the formation and on fracture length. So you, so that is, you don't always get to that, the radial flow, unless you have high permeability formation and shorter fractures and liquid in tight gas formation forget it you can't reach that radial flow. If you reach that radial flow and you see I'm saying if you reach that radial flow then that equation relating fraction length to skin factor would apply. So if you have tight gas formation, forget about this equation you cannot use. If you have high probability formation and it's liquid and short the fracture, then"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "tight gas formation, forget about this equation you cannot use. If you have high probability formation and it's liquid and short the fracture, then yes, you could calculate the equivalent skin factor. I think we are going to go a little beyond one hour here. Maybe we'll go to about another 20 minutes or so. For finite conductivity fracture, it gets more complicated because early on, you are going to see linear flow inside the fracture, which takes place in only the first few seconds, maybe up to a minute or so usually. So although theoretically is interesting, practically is not of great importance, unless you run extremely precise tests. And then you get to buy linear flow. And that is very interesting behavior. Because now you have linear flow inside the formation. So fluid coming from close around the fracture, not very far. And so it's coming from the area around the fracture moving linearly into the fracture phase and inside the fracture is moving linearly to the wood board. And"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "coming from the area around the fracture moving linearly into the fracture phase and inside the fracture is moving linearly to the wood board. And we're going to look at this a little bit more then you get to linear flow inside the formation. Once the pressure drop inside the formation is a lot higher than inside the fracture, then it behaves as if there is no pressure drop inside the fracture and you see linear flow inside the formation, then you end up seeing that elliptical fluid flow. That's very difficult to analyze, you can only match data, you cannot, there is no specific graph to it. It is not like square root of time or semi-log graph that you use in radial flow. Eventually you get to the pseudo-radial flow. If you reach that pseudo-radial flow, which is not common at all to reach it in fractured cases, unless you produce for a very long time, and you have a short fracture, you have fluid, you have liquid, and then you see that behavior too. So this is the early linear flow."}


created_at: 2023-11-18 18:31:57
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "very long time, and you have a short fracture, you have fluid, you have liquid, and then you see that behavior too. So this is the early linear flow. It is, as I said, it happens only for short time. I'm not going to go through the equations and details, but this is the only behavior where you do not see the fracture permeability, the Kf and fracture width together. In all other behavior, you are going to see KfW together as a product. And if you see KfW together as a product, that tells you, you can't analyze those pressure behavior to separate Kf from W. And this is one reason in analysis people talk about KfW or you talk about CfD, you don't talk about fraction probability. However in the design part you always talk about Kf and W as two separate components. Bilinear flow will not show if the conductivity is very low and if the conductivity is very high. It's very high, you don't have bilinear flow, it goes from linear flow directly to electrical flow. If the conductivity of the"}


created_at: 2023-11-18 18:31:57
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "is very high. It's very high, you don't have bilinear flow, it goes from linear flow directly to electrical flow. If the conductivity of the fracture is really, really low, and then you don't see that bilinear flow, you actually, the system will behave as if it is radial flow. So if your conductivity of the fracture is too low, then basically you don't have an effective fracture. There is a lot more stuff that one can discuss in this that it's beyond the scope of this lecture. Then I, for finite conductivity fracture, you can see, there's something interesting that appears here, is in early time, you can see that the slope is about quarter when I put log of dimensionless pressure, or log of delta P versus log of time, I see quarter slope, I see straight line that all parallel and see a quarter slope, I see straight line that all parallel and a half quarter slope. That makes the analysis of data like this very difficult. I'm, when there's implication to it, we're not going to discuss"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "and a half quarter slope. That makes the analysis of data like this very difficult. I'm, when there's implication to it, we're not going to discuss today. Today is just an introduction. However, it is something interesting because I look at the equation, dimensionless pressures versus dimensionless time. And I look at equation that looks like this. So where dimensionless pressure is a function of dimensionless time raised to the power of 0.25. And the equation has CFD, square root of CFD. If I go and, this is one of my favorite questions to students, I will let you think about it, and maybe Dr. Elgarhi will give it to you as a problem. If I substitute the parameters of dimensionless pressure, dimensionless time and dimensionless CFD, dimensionless fracture conductivity, and I start the cancelling parameters, I find out that fracture length cancels out. And the question would be, isn't it strange that the dimensionless pressure in a fractured system is independent of fraction length"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "cancels out. And the question would be, isn't it strange that the dimensionless pressure in a fractured system is independent of fraction length during the bilinear flow? So that sounds kind of strange, actually sounds very strange. And the question would be what is the implication of that? This is fairly important. It actually leads to very interesting conclusion. I will let you reach that conclusion yourself like what I do to my student when I teach. that I do to my student when I teach. Here, if I look at the linear flow inside the formation, you can see if CFD is very small, I don't have linear flow inside the formation at all. That's what basically, basically I'm getting to radial flow behavior to begin with. So CFD of 0.1 is too small. If I get to very high CFD, then I see that linear flow for some time. And as the conductivity gets, fraction conductivity gets smaller, the linear flow will start later in time and ends later in time. So it gets smaller and smaller. So you have a"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "fraction conductivity gets smaller, the linear flow will start later in time and ends later in time. So it gets smaller and smaller. So you have a profile, something like this, like what we saw in here, in between, between the quarter slope and this area. Okay. And again for finite conductivity fracture, we get an equation similar to what we see in infinitely conductive fracture, except now there is another term in the set of 1.1, the term here is function of dimensionless conductivity. Equivalent skin fracture can be calculated under specific conditions, as I mentioned, only happens when you, when, when the fracture length is very short, you have liquid, so that does not happen very often. We saw the equation in infinitely conductive fracture. For finite conductivity fracture, you can have this term N in it. There is a couple of approaches, that approach using N, it's the one I have been using, Sankule and others have another approach, we'll talk about it maybe later on. But the"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "that approach using N, it's the one I have been using, Sankule and others have another approach, we'll talk about it maybe later on. But the behavior N is very straightforward approach. I'm showing to you basically what it says that this term N is changes with, the equation would be one over, you have an N here, and you can see, N is, if you have very high conductivity, N is 2, is actually should be 1 over N, and if you're, as the conductivity gets smaller and smaller, you see going down this way, and it gets larger and larger. So, here Lf, sometimes you write it Lf over N, so Lf over N is, if you have infinite conductivity fraction like what we saw in the previous equation, L is equal to 2, as, as conductivity gets smaller and smaller, and it gets larger and larger, meaning that, basically the effective fraction length, it gets smaller. So as if your, your finite conductivity fraction, as if it can be represented by shorter infinite conductivity fracture. This happens only, you have"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "So as if your, your finite conductivity fraction, as if it can be represented by shorter infinite conductivity fracture. This happens only, you have to remember that, that's, that this is not just a general equation, this happens only after you reach the radial flow or the pseudo-radial flow behavior. Many people take it wrong and they think that you can always represent fractured well with radial flow system. That is incorrect. This is one reason when I predict production I don't want to use equivalent skin factor, I want to use fractional dimensions. Planning for fractional treatment, you can look at steady state or pseudo-steady state, people have done that before, or you can use transient behavior. use transient behavior. For, for steady state, there was a very interesting correlation, that it was originally published by, by Tensley and the other several people. Unfortunately, it had... had some problems, it was... I hate to say it, but there was some mistakes in... in... in... in"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "the other several people. Unfortunately, it had... had some problems, it was... I hate to say it, but there was some mistakes in... in... in... in the equation, I... I ended taking it and I... I redid the correlation and I published this back in, I think 1980 or 81, I can't remember, it was a long time ago, 40 years ago. But it is very interesting, because, let me, let me go to the equation where showing one is, is clearer. It, it tells you, basically, you, when you design a fracture, you don't want to be on that sharp curve. Because that sharp slope, basically, if you lose conductivity, you're sliding... Well, let me go back and say, here this is basically productivity and indices relationship. The difference between hydraulic fractured well and unfractured well. So you wanna be as high as possible. Here, mostly it is function of CFD. So, you don't want to design a fracture where you're sitting here. Because if you lose conductivity, and you're bound to lose conductivity with time,"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "So, you don't want to design a fracture where you're sitting here. Because if you lose conductivity, and you're bound to lose conductivity with time, you... the conductivity, the productivity of the weld declines very fast. You want to be on the flat line, but you don't want to go so far in the flat line, because, once you get to a certain point here, you can increase conductivity very much, but you don't increase productivity that much. So that graph was actually very interesting, and that is the reason, you know, you always hear about dimensions, fractional conductivity of 30. Actually we published that many, years ago and that is this curve is the reason for that the mesh's conductivity of 30. At the time we published it based on another term that will be 10 but it had pi in it so it was 31 and so on. So that gives you the historical reason, because when you get to CFD of 30, you're actually on the flat line, a little deep in the flat line. If you go to 50, it does not increase"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26092a4a-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "reason, because when you get to CFD of 30, you're actually on the flat line, a little deep in the flat line. If you go to 50, it does not increase productivity very much. It increases a little bit, but not very much. It increases a little bit, but not very much. So you, but you want to avoid being on that sharp curve. The reading suggested reading material would be, would be SVE monograph number 23, chapter 11. That's something that I wrote, if several, about 20 years ago. And it is very interesting looking at analysis and it talks also about fracturing. There is more stuff is written in chapter 15 in book, Will Construction. Unfortunately, the book Will Construction Construction, is out of print. It's very expensive to get. And so I do not know what to tell you about it. S.P. Monograph, number 23, that can be ordered from S.P. It is a very good book. It's about well testing. So if you are in well testing, I would recommend this book and the chapter 11 talks about well testing of"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "a very good book. It's about well testing. So if you are in well testing, I would recommend this book and the chapter 11 talks about well testing of hydraulic fractured well, but I've added a lot of stuff on hydraulic fracture design, some of the stuff we're talking about here. So these two chapters I wrote some time ago. That is, that is takes care of my presentation. Thank you for attending and we'll take just a couple of questions, other questions, if you have so many we can always answer them in email. If you want to access my email, I am with the University, it is very easy to get my email address, it is mysolomon, like what you see here, M-Y Solomon at uh.edu. That email does, that's an alias, but also you can find it as msolomon at central.uh.edu. So I have two of them. I will, you can reach either one. As I said, the presentation, PDF file of the presentation will be posted on research again in the next couple of days. So you can download it and look at it at your leisure."}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: 26092b8a-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "PDF file of the presentation will be posted on research again in the next couple of days. So you can download it and look at it at your leisure. Thank you, Dr. Solomon for this enlightening session. Now we'll move on to answering some questions by our honorable audience. Someone says, what kind of potential dangers questions. I'll move on to answering some questions by our honorable audience. Someone says what kind of potential, um, dangers oil based mud, um. Or sorry, oil based fracturing fluid can cause to the formation. We are going to when we talk about fractured design about fracture design, we'll be addressing issues like this, but simply said, you know, I work for a service company for some time, we always brought, if it's a new reservoir, the new reservoir that we're fracturing, you bring a sample of the rock, and you test it in different ways, mechanical testing to get Young's modulus for Sanz ratio and so on and so forth, like what we are going to discuss when we get into in"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "ways, mechanical testing to get Young's modulus for Sanz ratio and so on and so forth, like what we are going to discuss when we get into in situ stresses, so we can design the fracture properly from propagation point of view. You also test it against the different fluid that you want to recommend and you add additives you are going to see when we get in fracture designs there's so many additives you add to make sure that you don't damage the formation. So that is that is the brief answer when we talk about fracture design there will be more discussion on the subject. Okay, thank you. Now we have another question that says, what kind of benefits can we get from fracturing high permeability reservoirs? That's a good question. I don't have a presentation for this course on high permeability reservoirs, but let me tell you, in high permeability reservoirs like in the Gulf of Mexico, those reservoirs are not only high permeability, they are usually weak, meaning that as they deplete the"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "reservoirs like in the Gulf of Mexico, those reservoirs are not only high permeability, they are usually weak, meaning that as they deplete the formation, they collapse and the end losing permeability around the wood bore. It goes from 50 millidarcy down to maybe 1 millidarcy or even less and it goes into depth of several feet. So, acidizing or perforation does not help. So you fracture this formation and usually you design a shorter fracture. So those fractures, very high permeability fractures, we call them frac-pac. At least that was the commercial name for Haliburton, but other companies will call them frac and pac, for example, or hyper fracturing. So you end up having wide fractures, have high problem concentration, that is doing two things, is doing sand control, and spreading the productivity or the fluid flow over a long distance. So it can produce the same amount of fluid or more with a lot less pressure drop. This is the reason people call it frac pack because you're"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "So it can produce the same amount of fluid or more with a lot less pressure drop. This is the reason people call it frac pack because you're packing the fracture. When we get into testing, I am going to show maybe not exactly the design, but some of the testing. But it is an application that is very, very important. We have seen it a lot in the Gulf. You can't produce those worlds on the radial flow condition for too long without losing that productivity. Did I answer your question? I may go back and look at the fracture design and we add a little bit more on infraction and hyper. Okay, thank you. Someone asks, are there any problems in fracture orientation and inclined, not vertical? That's a very good question. I was not going to get into that, but absolutely. We are going to get into the extreme cases horizontal well. We are going to look at fractional horizontal well a little bit. But inclined well is even more complicated than horizontal wells. We've done some paper on the"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "to look at fractional horizontal well a little bit. But inclined well is even more complicated than horizontal wells. We've done some paper on the subject that we presented years ago. I do not know that they can see me or not. Can audience see me? Because I want to do something. Yes, they can see you, but I believe the camera is showing the top half of your head. Yes, now it's way better. You know, when you have a world that is inclined, inclination now becomes more complicated because you have to look at inclination in space. So it depends on the three stresses. Let us leave this question until I get to in situ stress. I may add a slide or two of things that we have done in the past. Most people don't look at it. However, we did fracture inclined wells. And you need to, when you say inclined wells, there are two things. There is deviation and there is inclination. They are two different things. Deviation is deviation from the vertical. So as, so deviation of zero would be a vertical"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "and there is inclination. They are two different things. Deviation is deviation from the vertical. So as, so deviation of zero would be a vertical world, deviation of 90 would be a horizontal world. And then there is inclination in space. So, so this is more a problem than it appears. One thing we did years ago, where fracturing deviated well, that's also inclined in space. And the idea was, since obviously we can't control the stresses, the stresses are the way, whatever they are, what we try to do is to make it not inclined from stresses, but deviated. So if you do deviated well, and you perforate in the top and bottom, the top side of the well and the bottom side of the well, you end up having a vertical fracture that is propagating from the well. If you, if it's inclined with respect to stresses, if you, and you do that, then you still, if you perforate throughout the whole pay zone, you still get a vertical fracture that get inclined in space. I have done some more work in the"}


created_at: 2023-11-18 18:31:57
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 01-04.txt", "chroma:document": "if you perforate throughout the whole pay zone, you still get a vertical fracture that get inclined in space. I have done some more work in the area, and it is really, really interesting. It is more complex than even horizontal ones. Thank you Dr. Solomon. That's about it for the questions today. It was a pleasure having you on Paiapetro. Thanks for joining us, and thank you everyone for tuning in with us today. Today's session will be uploaded on Payopetro YouTube channel. You might want to check that out for your quiz. Thanks again. Have a great day. Thank you very much ladies and gentlemen. you"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "Good evening, good morning and good afternoon. Hope you are all doing well and staying safe. I'm Maryam Shraif, a senior petroleum engineering student at the Lebanese American University, and I'll be moderating today's session. So it's my pleasure on the behalf of Payo Petro to welcome you all to the second lecture of the online course Hydraulic Fracturing, which has been presented by a special distinguished speaker, Dr. Mohamed Salomon. I'm sure his participation with us today the Department of Petroleum Engineering and Manufacturing. Which has been presented by a special distinguished speaker, Dr Mohammed Solomon. I'm sure his participation with us today will benefit all participants. With that I advise you to give your full attention to his informative session today. So let me begin by reintroducing our guest speaker for today. Professor Solomon. So Professor Solomon, the chairman of the Petroleum Engineering Department at University of Houston. Dr. Solomon has a long industrial"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "Solomon. So Professor Solomon, the chairman of the Petroleum Engineering Department at University of Houston. Dr. Solomon has a long industrial and academic experience. He holds 35 patents on fracturing operations and analysis, testing and conformance applications. He is the author and co-author of over 250 technical papers and articles in various areas of petroleum engineering. Dr. Solomon is a registered professional engineer in the state of Texas. He is also a distinguished member of the Society of Petroleum Engineers and Fellow of the National Academy of the Inventors. To highlight, he has authored several book chapters on stimulation and testing. Additionally, he is the primary editor of Fracturing Horizontal Wells, published by Macro Hill in 2016. He is also the co-author of Optimization of Hydraulic Fracture Stages and Sequences in Unconventional Formations, published in 2018 by CRC. Finally, Dr. Solomon holds a Bachelor of Science with top honors from Cairo University and a"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e132fb48-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "in Unconventional Formations, published in 2018 by CRC. Finally, Dr. Solomon holds a Bachelor of Science with top honors from Cairo University and a Master's and a PhD degree from Stanford University. Thank you everyone for attending, thank you Maryam for the introduction, thank you Ahmad for arranging this teaching, giving me more work to do than I... as if I don't need any more work. Anyway, this is the second lecture. We talked last week about the history of hydraulic fracturing. I should have also mentioned last week that Mr. Buddy McDaniel is an old friend of mine and a colleague that we did a lot of work together, was the biggest contributor to the writing on fracturing, history of fracturing, fracturing was both vertical and horizontal. So if you, when you read this presentation, please remember that I should have acknowledged him as a very knowledgeable person that we did a lot of work together. During, in last week I also talked about fluid flow, and I mentioned the pseudo"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "as a very knowledgeable person that we did a lot of work together. During, in last week I also talked about fluid flow, and I mentioned the pseudo radial flow and elliptical flow. So what I did, I'm having another four slides here to show you some numerical simulation of how the fluid flow would look. Just a simple case where I have a vertical hydraulic fracture in a formation and make it penetrating the whole formation, to show you how the fluid flow would look. This, I'm showing a couple of illustrations, it will be two slides on infinite conductivity fractures and the two full slides on finite conductivity fractures. So here I'm saying CFD and if you remember the definition of CFD which is permeability of the fracture times the width of the fracture divided by formation permeability, and also divided by fracture half-length, one wing of the fracture. And here I have very tight gas formation, so it takes, so the conductivity basically infinite, infinite meaning that the pressure"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "of the fracture. And here I have very tight gas formation, so it takes, so the conductivity basically infinite, infinite meaning that the pressure drop inside the fracture is negligible relative to the pressure drop inside the formation. And you can see here, the behavior looks very much as if I have just a line inside, inside the formation. That's what will give me linear flow. After a long time you can see the pressure drop around the formation is demonstrated here. If I look at the outer boundary where the pressure has been significantly affected, you know, the rest, the red one area, the red area, basically saying we have not affected this area at all. So nothing coming out of, or very, very little coming out of this red area. Most of the fluid is coming out from this affected area. And you look at the affected area, it's elliptical shape, but it looks almost like a circle. So it is almost radial flow, and this is the reason you call it pseudo-radial flow. If I have finite"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "shape, but it looks almost like a circle. So it is almost radial flow, and this is the reason you call it pseudo-radial flow. If I have finite conductivity fracture, you can see the effect is not as strong and you don't see the end of the fractures right away. So it takes some time to see the end of the fractures right away. So it takes some time to see the end of the fracture. That is the bilinear flow. If you remember, we talked about that a little bit. And you can see with time, you end up seeing further and further into the formation, but the elliptical behavior is more dominant here till eventually you reach the pseudo radial flow. Pseudo radial flow which is almost radial flow, it is still kind of elliptical, however the major and minor axis of the ellipse are almost equal. If they are almost equal so they are almost having radial flow. So that's the reason you would call it pseudo-radial flow. Fracturing part of it is fluid flow. So we discussed that. We need today we want to"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "flow. So that's the reason you would call it pseudo-radial flow. Fracturing part of it is fluid flow. So we discussed that. We need today we want to talk a little bit about rack mechanics and in-situ stresses. Next week we'll talk about fraction mechanics and last week we'll talk about testing. And please remember, please remember that this is very introductory, you know, we don't go in things in huge details. We teach graduate class in, I taught it in Texas Tech and we'll teach it here at UH, where we go into all those areas in a lot more details and theory. So it is over 16 week, three hours per week and homework and midterms and all kind of things. So let us talk a little bit about Rack Mechanics because that we need to understand just before we get into the stresses. So what is R mechanics? Basically, it is a discipline that you, and that you use to describe the behavior of underground formation of rock under in-situ stresses or sometimes externally applied loading conditions."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "and that you use to describe the behavior of underground formation of rock under in-situ stresses or sometimes externally applied loading conditions. That's what you do in hydraulic fracturing. And when you couple the fluid and the rock mechanics together, that's when you talk about geomechanics. And we'll be talking about both in the rest of the hour. Is it important to study rock mechanics and geomechanics in petroleum industry? Absolutely. Absolutely, unfortunately it has been ignored for a long time in teaching undergraduate and graduate classes and that's a mistake because it's important in drilling, borehole stability, what happens as you drill with it. We'll mention a few little things as we talk here. Formation breakdown, if you're down a whole pressure or the wheelbarrow pressure, if it's too high, you could fracture the formation. If it is too low, you could collapse the wheelbarrow. So it's very important to understand all this relationship with the rock mechanics and the"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "If it is too low, you could collapse the wheelbarrow. So it's very important to understand all this relationship with the rock mechanics and the fluid flow. Stimulation, obviously, is very important to understand all this relationship with the drug mechanics and the fluid flow. Stimulation obviously is very important. Fracture initiation pressure, we are going to look at one equation here. We spend a little bit of time on it for fracture initiation pressure because it's very important to understand. Then next week we'll talk more about the fracture propagation pressure. To initiate the fracture requires certain pressure. It's going to be a little high pressure. People observe that once you fracture the formation, then your propagation will be at a lower pressure, but you can pressure that can be increasing with time. And one has to be able to analyze that propagation pressure. So we'll be talking about that both next week as well as in the testing part. Then we, all of that related to"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "to analyze that propagation pressure. So we'll be talking about that both next week as well as in the testing part. Then we, all of that related to fracture geometry and designing of a fracture, that's all important. Then you get into production, and then ... then there is a lot of aspects, so in rock mechanics, failure of the formation, sanding. We're not going to get into sanding at all in this ... in this course, because it's more hydraulic fracturing, but sanding is very important and ... hydraulic fraction. But sanding is very important and in a graduate class we end talking about sanding, the onset of sanding and the calculation of how much sand you produce. You want to talk about some of the assumptions we work with. we can say well formation, many times, especially when you study well testing, they tell you homogeneous, the formation is homogeneous and isotropic. And there are two different things. Homogeneous formation means that if you take one element in the formation, it's"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "is homogeneous and isotropic. And there are two different things. Homogeneous formation means that if you take one element in the formation, it's basically represented the whole body as the whole formation. That's a little different for being, so many of the formation we look at, many of the assumptions we make is the formation is homogeneous. Really if you look at the formation at a very small element, they are really not homogeneous, but it is distributed so much that many of the formations, they behave as if they are homogeneous formations. So, we'll look at some of this, hopefully we can spend more time on it, because some of heterogeneities can be very important. When you get into heterogeneous formation, such as dual prostheses, shale, carbonate formation, this have very strong effect on fracture propagation. We deal with it a lot in our work, especially when you get into shell formation and when you analyze data. Isotropy, whether you call formation isotropic or anisotropic,"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "in our work, especially when you get into shell formation and when you analyze data. Isotropy, whether you call formation isotropic or anisotropic, that means a dependence on direction. So a formation may be isotropic and homogeneous, it may be anisotropic and homogeneous. So if I have a formation that is say permeability in one direction is different from the other, so it can be homogeneous but it's still anisotropic. Isotropic would mean that properties in various directions are the same. Now when you talk about rock mechanics, many times we make the assumption that it is, the formation is linearly elastic. Basically linearly elastic is as if you're looking at spring. So you push the spring down, you compress it, you relax, it goes back to original shape. So, and we'll describe it a little bit more detail mathematically in a minute. But basically all we're saying here is the formation, it will be, will disappear once you remove the external forces. So how realistic they are?"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e13301e2-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "But basically all we're saying here is the formation, it will be, will disappear once you remove the external forces. So how realistic they are? Essentially I talked about that. Homogeneity many times is a good assumption unless you get into a dual prostate or natural fracture formation or it becomes important. We are going to see that the importance of heterogeneities when you talk about fracture design and especially when you talk about analysis. When I get into analysis I will show you something that we have been doing, and especially for shell formation, that heterogeneities have to be considered, the presence of natural fractures will have to be considered, which makes the formation heterogeneous. Isotropy, usually in a horizontal plane, it may not, probably not very, very much, but we many times we assume isotropy, but you are going to see in testing again, and even in design, it can have an effect. Linearly elastic material, if you have, if we have hard rock and we'll talk more"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "to see in testing again, and even in design, it can have an effect. Linearly elastic material, if you have, if we have hard rock and we'll talk more definition of what hard rock is, if you have, if we have hard rock like sandstone, then the behavior would look very much like linearly elastic, but if you get a soft rock, such as when we fracture in Gulf of Mexico and I'm sure in areas where you live and you work. So in Gulf of Mexico they are soft rock, so the behavior is different. It cannot be exactly considered linearly elastic. So there is other ways to handle that behavior. So if I look at it, when I say, and there will be more of this in a minute, when I say linearly elastic, if I plot stress versus strain, and we'll talk about this in more in a few minutes. If I increase the stress, I get more strain. So basically it is like if I have a core and I compress it very much as if I'm compressing, you look here on the left hand side as if I'm compressing a spring. So if I compress it,"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "a core and I compress it very much as if I'm compressing, you look here on the left hand side as if I'm compressing a spring. So if I compress it, it gets shorter. And then I release it, it goes back to original value. And if you look at here, stress versus strain, so it's going in a straight line. If I release it, it goes back on that straight line. So not only this is linearly elastic, but there is no hysteresis. So it goes back on the same line. Does it always work this way? No, but this is a simplification that many people use. In reality, it may look like the curve we have here beside it and that early part of behavior which is an elastic strain we use in some special testing. Unfortunately, I'm not going to get into that even in the testing part. It is too specialized, but we have used it many times. And when we get to testing, we may be able to say a word or two about it. And so eventually in any of these cases, if you have, if you've studied material science, you will, they"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "may be able to say a word or two about it. And so eventually in any of these cases, if you have, if you've studied material science, you will, they will tell you, you know, after some time, if your stress gets too high the formation may fail. So you can have failure of the formation that's a plastic behavior so it cannot be reversed. Poor elasticity is very important concept to understand with it affects the fracture, affects the drug behavior, and we'll talk more about it in a few minutes. For example, here, this would having two straight lines showing whether it is drained, same like the one above, stress versus strain. I probably should have defined what stress is. Stress is and have the units like pressure is psi, force per unit area. However it is not the same as pressure. Pressure usually is is used to describe fluids. So pressure is a scalar quantity. Stress is a vectorial quantity, meaning that it has orientation. We'll see that in a minute. So I can, here I'm saying whether"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "is a scalar quantity. Stress is a vectorial quantity, meaning that it has orientation. We'll see that in a minute. So I can, here I'm saying whether the rock does not have any fluid in it, it will follow different curve or different line than if it has fluid on it. And then we'll talk about stiffness versus frequency. You know, we'll get into that in a little bit, because we can sometimes measure the behavior of the rock using a sonic lab or seismic or what one would call a static behavior basically like what you are seeing here. So what are the important parameters that you want to look at? The most important parameters for elastic properties you want to look at are Young's modulus, Hossain's ratio, and Biot's constant. And we'll talk a little bit about each of those. For stresses, I want to look at the total and effective stress. So, keep that in mind, I will describe each one of them in a minute. So, when I look at stress, if I have a piece of rock, like what I have on the left,"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "keep that in mind, I will describe each one of them in a minute. So, when I look at stress, if I have a piece of rock, like what I have on the left, and I'm having stress, and you can see, I have a force, the force has an orientation. That can be, I can break it into, it's two main components, very much like what you study in math. So, I can break this two compo... this force in two components, one parallel, and one perpendicular to the rock. So the parallel one is my shear force and here is the perpendicular one is normal force. So if I take that normal force divided by the area, that gives me the stress, that would be my normal stress. The shear stress is again the same thing, take the parallel force divided by the area. So if I, if I look at a piece of rock, you look at that nice looking graph, if I have a piece of rock downhole many hundreds or thousands of feet deep, it's exposed to stresses in all directions. It's not only in one direction, it's exposed to stress in all"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "many hundreds or thousands of feet deep, it's exposed to stresses in all directions. It's not only in one direction, it's exposed to stress in all directions, but you can bring those stresses into three principal stresses. If you study electrical engineering, you remember the right hand rule and left hand rule. So they have three, you break those stresses into three perpendicular stresses and you call them three principal stresses. So they are all perpendicular to one another. Usually, so usually one is vertical and two are horizontal. In some cases there may be some orientation to it. You know, if you are beside a mountain, you know, like near the Himalayas, near the Andes mountain here in United States, near mountains these things will change, we'll talk about that in a minute. But you break the stresses into three perpendicular stresses, a vertical and two horizontal. So, I will call that SV, that's my total stress. So, that's vertical stress. The two horizontal stress, one usually"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "a vertical and two horizontal. So, I will call that SV, that's my total stress. So, that's vertical stress. The two horizontal stress, one usually is bigger than the other. So, I'm going to call them SH-Max and SH-Min. And then your fluid will have, and that will have a pressure, so there is a pore pressure inside the pores, because we don't have completely solid, so there's pores inside, and this will have pore pressure, when it's important to think about that. And then you have also, the compressive strength of the rock, which is, if I, the un, the unconfined compressive strength is the, the stress that will cause the fra... the, for me, the rock to feel under compression, when it is completely unconfined, and you call that, unconfined compressive stress, and you have the tensile strength, stress, strength of the rock. We talked about that last week. The one thing you have to remember, like anything in nature, you move from one point to another, you want to use or you want to follow"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "last week. The one thing you have to remember, like anything in nature, you move from one point to another, you want to use or you want to follow the path of least resistance. So if you are sitting at home, you want to go out, the path of least resistance, you get out of the door, you go downstairs and so on and so forth. The same thing with fracture, it has to follow the path of least resistance. What is the path of least resistance for the formation for a fracture to go? You can see if I have three stresses, the fracture will have to become perpendicular to the smallest stress. Because that is, that is the path of least resistance that we, we have. So, so a hydraulic fracture will be perpendicular to the smallest principle stress, the least principle stress. So that is my path of least resistance. Don't tell me, you know if I ask you this question, you have to tell me it is perpendicular to the minimum stress. It's perpendicular to minimum stress, not parallel to the highest stress."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "question, you have to tell me it is perpendicular to the minimum stress. It's perpendicular to minimum stress, not parallel to the highest stress. They are, mathematically they are different. You know, the answer would be when I ask what's the orientation, it is always perpendicular to the minimum principle stress. So let us look at, let's look at stresses and basic theory. This is very famous, grab been published by so many different people. So I just took it from, I think the first company that published it was GMI, although when I was in Halliburton, we use something very, very similar to that. And so, so here I'm going to look at different types of falls. And that will be an indication of the, of the regime, the stress regime that we've got. So if, if I have the stress regime that we've got. So if I have a stress regime in what I'm looking at, the formation I'm looking at, where the vertical stress is the highest, and then you have the maximum horizontal stress, and then you have"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "at, the formation I'm looking at, where the vertical stress is the highest, and then you have the maximum horizontal stress, and then you have the minimum horizontal stress. If you have a fault, then the fault will go, I always like to show it with the illustration, but anyway this side of the fault will go down. It goes down because you have very high stress pushing into it. So if I So if I fracture this formation, if I have this situation which I'm going to call it normal stress regime. If I fracture this situation, what kind of fracture do you get? Well the fracture has to be perpendicular to the smallest stress. And here the smallest stress is the horizontal stress, SHMN. So that tells me that the fracture will be vertical and it is perpendicular to SHMN. So I'm going to jump to the reverse stress regime, the last one. Here, this is not as common. Usually the normal stress regime is the common regime. You see in most situation for formations that are deeper than 1500 feet or so,"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "not as common. Usually the normal stress regime is the common regime. You see in most situation for formations that are deeper than 1500 feet or so, which is the cases that we usually fracture. Some are shallower than that, but usually you, it's deeper formation and what you see is normal stress. And when I say usually, there is always exceptions to the rules. So let's go back to the, no go down now to reverse stress regime. What reverse stress regime, when your vertical stress is the smallest. So your maximum horizontal stress is the highest, then followed by minimum horizontal stress, followed by the vertical stress. So if I fracture a formation like this, what do I see? Well, I'm going to see a horizontal fracture. And do you see it sometimes? Yes, it could happen. As we are going to look at what causes the stress in underground formation. I've seen it, not very often, but I've seen it sometime, especially near mountains. I've seen a case like this in South America and I,"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "formation. I've seen it, not very often, but I've seen it sometime, especially near mountains. I've seen a case like this in South America and I, unfortunately, we never got the data. I wanted to get the data very badly, because it was, it was a very interesting, a different situation than what you see. And it has its signature, when you run testing and stuff, when logging, you see a different signature of the horizontal fracture. So, you don't see that very often. Now, in the middle, I have a strike-slip situation. A strike-slip situation and when the vertical stress is in the middle. So the highest stress is HS max, the smallest stress is SHMN. The minimum horizontal, minimum horizontal stress is the smallest. So, if I fracture it here, what happens? Well, what happens is, we already know that, that a fracture is from a perpendicular to minimum horizontal stress or minimum stress, so the minimum stress is horizontal, so I have a vertical fracture perpendicular to my minimum stress."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "minimum horizontal stress or minimum stress, so the minimum stress is horizontal, so I have a vertical fracture perpendicular to my minimum stress. However, situations like this you could have a problem. One is many times it becomes a T-shaped fracture. It hits the boundaries between layers and you end up having a T-shape. So you have a horizontal part of the fracture and that when this happens, it will cause all kind of issues during the hydraulic fracturing. Another big issue that we are not going to get into is during drilling. Because now if you, especially if you plan to eventually drill a horizontal well, as the well is deviated you need, because as we say, is deviation, deviation from vertical and inclination from north, from your stresses. So you could have a lot of problem during drilling. We are not going to get into that, but this is a very important issue. So if you suspected that you have a slack slip situation you have to test the formation, you have to test it, because"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "this is a very important issue. So if you suspected that you have a slack slip situation you have to test the formation, you have to test it, because it's important to know which regime you are in. That gets you designed a drilling pad and a fracturing later on. Years ago we actually, a company, spent a lot of money, we worked with them in order to figure out whether it was a strike, slip, or normal stress. Luckily for them, eventually after we ran all the testing, it was normal stress. So let us look at a couple of cases here kind of quickly. Here I have a fault. What is this normal stress? Usually when I teach, I ask a student to tell me, here I cannot see you. And so I'm going to tell me here I cannot see you and so I'm going to tell you here you can see this party here went lower you see this is a little higher so that is that is normal stress regime. This is a similar situation. You see the fault here and you see that little man is working, right? You can see that this side, the"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "stress regime. This is a similar situation. You see the fault here and you see that little man is working, right? You can see that this side, the right-hand side, part of the formation dipped down. So this, at the time time it was normal stress regime. How about this one? If you look at it, and you look at it from like from far away, you can see as if the formation just slipped sideways. That's a strike-slip situation. How about this? You see the fault here? And rock actually bent as if it is, as if it's a soft thing, but under high pressure and the high temperature, even rock will turn around. That's the reason we see an antic line and all this geologic formation. So this is, you can see this right-hand side dropped below this right side, that left hand side part of the rock, that is reverse faulting. So this must have been, at the time it happened, must have been extremely deep. And not only deep, that's high pressure and high temperature, but also was exposed to some external, very"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "it happened, must have been extremely deep. And not only deep, that's high pressure and high temperature, but also was exposed to some external, very high external forces, that, that caused the horizontal stresses to be higher than the vertical stresses. We'll see why. So what, what causes all those stresses? We'll go through some of them, not all of them. The biggest one is the Tectonic plates. of them, not all of them. The biggest one is the tectonic plates. Let us look at it, then we'll talk about topography, the mountains, lateral variation of the thickness of Earth, sometimes localized load, and it may be just the weight of, weight of the rock. Thermal stresses are, can be important also. We, we sometimes take advantage of this in the fracturing process. I will talk about it a little bit. So, tectonic plates, if I, if I look at this map and this, when this map was created, as you can see at the bottom, here, by Karlsruhe University. You know, I, when I hear that, it's like this,"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "map and this, when this map was created, as you can see at the bottom, here, by Karlsruhe University. You know, I, when I hear that, it's like this, because I, I spent one summer actually, as a graduate student at Karlsruhe University, University of Karstu. It's a interesting place. A very strong, technically. ... You, you look and you find the Earth is broken into pieces. ... You look at this, for example you look at ... Africa is sitting on a tectonic plate, that looks very much like Africa, only part of it is above water, the rest is under water. South America is similar, North America is similar, ... Asia, Euro Asia it is one tectonic plate. Actually it can break the tectonic plates into, there is major ones and, but you can break it into sub-major ones. ... I can tell you, here in, in United States, you have this tectonic plates here and it can cause earthquakes, and that's the reason for behind the earthquake in San Francisco, back in 1905. Your tectonic plates here, you can see"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "and it can cause earthquakes, and that's the reason for behind the earthquake in San Francisco, back in 1905. Your tectonic plates here, you can see breaking in ... through Iceland. We'll look at this in ... in a second. So, Earth is alive. Actually, people did not realize that that there is such a thing, ... as tectonic plates, until early 20th century. ... Someone, someone wrote a paper on the subject, and people did not believe him. They, because, they thought it's just a coincidence, that Africa and, and North and South America look the way they look. Till after Second World War, and the exploration of bottom of the ocean, revealed that there's actually this like a volcano type line here, and it was in this area, if you see around Indonesia, this is what caused the tsunami back in 2000 something, 2005 maybe, maybe around that time. But it was a huge tsunami that killed a quarter of a million people. And, it was caused because of the tectonic plates, because tectonic plates they"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "But it was a huge tsunami that killed a quarter of a million people. And, it was caused because of the tectonic plates, because tectonic plates they keep moving. ... For example, the movement here across Iceland, it ... basically the Euro-Asian plate and the North American plate, they go away from one another about an inch per year. It sounds like it's, it's very small amount, it's a very small number, but over millions of years that's a, becomes a huge, huge distance. ... So, so here, what, what they did in Karst Ruins, they were trying to find the stresses. So, for example, an, an area like here, South Africa, this is, this is thick arrows, this is an indication of a strike-slip situation, when you have arrows going into one another like that. If they are going away from one another like this red arrows, that tells me I have normal stresses. I usually give students a homework to go download another map of your area. homework to go download another map of your area. In US, I asked"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "I usually give students a homework to go download another map of your area. homework to go download another map of your area. In US, I asked them to download the map for United States and explain what the stresses that we have. Those are regional stresses, does not mean that local stresses will be exactly the same. That is, we already found that a long time ago that this is not the case in South Texas, although it looks like you have some strike-slip here, where many, many areas were actually normal stress, and the stress orientation changed across, across a fault. Okay. ... Let's look, this is just showing part of the Alps is actually, ... is from Africa, because you have the African plate and, and ... European North, Euro-Asian plate are colliding, and the African plate is basically going on top of the Euro-Asian plate. That causes a lot of stresses. If you go back to this map and you see, it's huge stresses near the Himalayas, near anytime you have a mountain. In Iceland, I"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "a lot of stresses. If you go back to this map and you see, it's huge stresses near the Himalayas, near anytime you have a mountain. In Iceland, I downloaded this map from Google, you can see in one side this is Europe, on the other side this is North America. So there is a bridge that you go from one side to another, you are crossing from the Euro-Asian plate to North American plate. And this distance keeps increasing. So, in lifetime of a person, it goes away by 6 feet. And the way it happens, and that's the reason behind the Tsunami, is one tectonic plate may be going under the other or getting separated. And what happened in the tsunami, is you know, although we say it moved about one inch per year, does not mean it is going very smoothly. In the tsunami there was no movement for a long time, and then it jumped, it built up a very high stress, and basically one plate jumped over the other, it moved 20, the estimation is 25 feet, it moved the water, although it may not, if you are"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "stress, and basically one plate jumped over the other, it moved 20, the estimation is 25 feet, it moved the water, although it may not, if you are sitting in the top of the water here in a boat, you don't really feel it very much, but as it comes closer to the, to the shore, it goes from, from inches into many, many feet, and so it has catastrophic effect. And that's what it causes a lot of stress. Another, the thinning of Earth, basically the lithosphere. And you look at, I have to give you example, the Gulf of Mexico is getting thinner and thinner, so the stresses change. So you find that your minimum stress, if you are here near New Orleans, your minimum stress is like this, and your fracture is perpendicular to it. If you are in Mexico, the minimum stress in different direction, and the fracture is perpendicular to it. So, does not mean that in the Gulf the orientation is the same everywhere. So, that is one reason people will have to test the formation to, to tell the orientation"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "that in the Gulf the orientation is the same everywhere. So, that is one reason people will have to test the formation to, to tell the orientation of stresses and magnitude of stress. We'll talk about ways to do that next week. Localized loads like, like salt domes, so you, you have salt domes, a salt, salt domes is ... under the high pressure and temperature it, it flows. Salt will ... although it may be hard, when you take it to the surface, but then down hold it, it flows. The same thing with chalk, you know the... we have fractured the chalk formation, and if you look at chalk, in the surface, when you take a sample, the surface is very hard, but downhole is flows like, not exactly like fluid, but it, it creeps very much. And so, soft dome, it moves and it can cause stresses, so, I don't have a graph for it, but, if you go down hole, if you take a cross section, you can see for, it's pushing the formation up and the oil will be trapped, will be trapped between the solid dome and"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "if you take a cross section, you can see for, it's pushing the formation up and the oil will be trapped, will be trapped between the solid dome and the formation, because solid dome has basically zero permeability. So you drill on the side of the solid dome, so as you move around, the orientation of fractures will change, because orientation of stresses will change. Gravitational stress is ... is interesting, ... you, basically it is weight of the rock. So your vertical stress in most cases it is nothing but the weight of the rock. So if I have various formation between surface and down hole, all you are doing is you are integrating in that way. You know, so it is an easy equation to do this integration, if it is, you can break it into various layers and add the stresses. If you do not know the value, most people will say, okay, what is my specific gravity of sandstone? If you remember, if you multiply the specific gravity by 0.433, you get your gradient. And so that gradient for"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "is my specific gravity of sandstone? If you remember, if you multiply the specific gravity by 0.433, you get your gradient. And so that gradient for sandstone is about 1 to 1.1 psi per foot. So if I do not know anything about the formation, I'm just making a very quick estimate, I would say okay my formation is 5,000 feet deep multiplied by 1 psi or 1.1 PSI per foot, then my vertical stress should be between 5,000 to 5,500 PSI. So that is an easy way to do it. If I give you a formation and said, okay we have all this formation, here is the specific gravity of each rock, some of them maybe 3, 3.6, maybe less, multiplied by 0.433, so if it is a sandstone is 2.65, then approximately. So, 2.65 times 0.433 is about 1.1 feet, type of foot or so. But, if I give you information, you need to do it correctly, you, you information you need to do it correctly. You can do it easily. And that's what exactly what log would do when they calculate stress for you. All they are doing is calculating the"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "correctly. You can do it easily. And that's what exactly what log would do when they calculate stress for you. All they are doing is calculating the vertical stress. We'll talk in a minute about calculating the horizontal stress. So you basically are integrating. If I'm in water, then part of it is water, you can see the equation, part of it is in water, part of it in, in, in the rock. So, in water, the specific gravity is 1 times 0.433, so, I have 0.433 psi per foot. So if I'm drilling in, in offshore well and water depth is, let's say, 2,500 feet, which is not, not really that deep in what we do now. And so you, that will be 2,500 times 0.433, so it's almost a thousand PSI, a little higher than a thousand PSI, and plus the weight of the rug. So let's look at the mechanical properties, the Young's modulus and Poisson's ratio, and Barth's constant. So we do it experimentally like what we have done that personally, we've done that in the lab many times, and we do it also from logs. So"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "constant. So we do it experimentally like what we have done that personally, we've done that in the lab many times, and we do it also from logs. So if I do it in the lab, and there is a difference between the two, the difference is kind of important. If I do it in the lab, you know, I get a plug, or a core, and apply stress, I keep varying that stress, the force, I increase the force, so I'm increasing the stress, and I build, then I take the change in height of that plug, and divide it by the total length. That give me the stress. So delta L over L is the strain. The force divided by the area is my stress and draw this straight line. And the slope of the straight line is my Young's modulus. Okay, Young's modulus for a hard sandstone may be, may be 5, 6, 7 million psi. This is, the stress is in psi, the strain is unitless, is dimensionless parameter, because it's length divided by length. So, ... so if I have hard sandstone, maybe 5, 6 million, we'll give you a table later on, about"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "parameter, because it's length divided by length. So, ... so if I have hard sandstone, maybe 5, 6 million, we'll give you a table later on, about the values. So 5, 6 million PSI. If you work in industry, most people will say 5 or 6, meaning 5 or 6 million, not just the five or six, but... So, five, six million PSI, and I'm talking in, in English units. If you work with metric units, then you need to translate that. ... And the stiffer the rock is, the higher the slope. So, if I go into softer rock, you get smallerness, the slope is smaller, so is smaller Young's modulus. Okay? Now, Poisson's ratio, let's talk about Poisson's ratio, then we'll give you a table. ... Poisson's ratio, let's talk about Poisson's ratio, then we'll give you a table. If I repeat the same, if I'm running this experiment again, and I'm applying this force, not only I'm measuring the change in, in strain, I'm getting, this rock is getting wider, so there is, there is axial strain, which is Delta L over L, but"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "I'm measuring the change in, in strain, I'm getting, this rock is getting wider, so there is, there is axial strain, which is Delta L over L, but there's also lateral strain which is the change in radius divided by radius, or you can call it change of diameter divided by diameter. And if I take the ratio of the lateral strain divided by the axial strain, that gives me what we call Poisson's ratio. Poisson was famous mathematician, French mathematician back in many years ago, in 1700s or so, you can see this. That ratio has to be less than 0.5 for a rock. If you run, you're running these experiments on a rock, that ratio, that Poisson's ratio is definitely less than 0.5. If you, if I give you a problem, and I've done that before, trick the students, if I give you a problem and you end up calculating Poisson's ratio 0.5 or larger, you, unless I wrote the problem wrong, which is very unlikely, or you made a mistake, which is probably the case. It happened in an exam that I have given."}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "I wrote the problem wrong, which is very unlikely, or you made a mistake, which is probably the case. It happened in an exam that I have given. And so I had to tell the students, Hey, you calculate a value of 0.5 or higher for percentage ratio, you are making a mistake. You need to look back into it. And why is that? And, why is that? Point five means that the rock cannot carry any load. So it's almost like fluid, like liquid. So obviously that is not the case. And I used to give a problem to, for students to understand that better. Okay? Then, then you have shear modulus, shear modulus basically deformation, if you apply force, and then you, shear force, then, then it will deform the rock by an angle, Theta. And, shear stress, shear modulus, it would be shear stress divided by this angle, in radians, not in degrees. And, you know the, Pi is basically 180 degrees. Okay, but you can actually, you can calculate shear modulus, it is related to Young's modulus and Poisson's ratio. So if"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "Pi is basically 180 degrees. Okay, but you can actually, you can calculate shear modulus, it is related to Young's modulus and Poisson's ratio. So if you know Young's modulus and Poisson's ratio, you can calculate shear, shear modulus. It's interesting that they are all things that are related to one another. Young's modulus and Poisson's ratio are independent variables. I'm falling behind very much, but, so it's probably another half an hour or so. Bulk modulus is actually the inverse of compressibility. So if I apply stress around the rock, the volume gets smaller. So it is essentially one over compressibility, except that we call it, in rocks we call it bulk modulus, and again its bulk modulus is related to Young's modulus and Poisson's ratio. So here is the relationship between one and the other in this table. That's assuming isotropic material. The values you have, you can see, Young's modulus for granite, it can be 10 million, and this all in PSI. In shale it may be, shale,"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "material. The values you have, you can see, Young's modulus for granite, it can be 10 million, and this all in PSI. In shale it may be, shale, shale can, you can have soft shale and hard shale. Most shales are not as hard. This is here, we're talking about hard shale that is almost as high as, as rock. But steel would be 20 to 30 million. Coal seam is 0.3 million. Let's look at sandstone. Sandstone can get higher than 4 million. With percent ratio, it's usually higher than zero, but percent ratio has to be less than 0.5. Usually, in, in what we deal with, the confining shale usually is softer than sandstone. And this is a very interesting parameter, we are going to look at it in a minute. But let me first talk about the parameters we looked at so far, Young's modulus and Poisson's ratio, shear modulus, this we call them static measurements. Dynamic measurements is where you are vibrating the grains. So you want to vibrate the grains, what you do is, you apply a sonic wave. Sonic wave"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "Dynamic measurements is where you are vibrating the grains. So you want to vibrate the grains, what you do is, you apply a sonic wave. Sonic wave will vibrate the grains. And, your vibration happens either, either longitudinal, as you can see in this picture, or transverse. So, if you are in one place, and you can see the, the reference of, of this slide, and I find it like an interesting slide. So, you can see there is vibration going longitudinal or transverse. So if I apply a sonic wave, the wave either will go compressional wave, so it moves from one place to another. So if I have a source in one, say at the bottom of the well, and I have a receiver a little higher, I can hear the compressional wave coming in, and then I hear the shear wave coming after it. Okay, so, I hear the compressional, then I hear the shear wave. I hear the compressional, then I hear the shear wave. The difference, the difference in time or in velocity of the two, is an indication of Poisson's ratio. So, so"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "then I hear the shear wave. The difference, the difference in time or in velocity of the two, is an indication of Poisson's ratio. So, so here if I'm listening to it, I think that, So here, if I'm listening to it, I think that, DTS was the shear divided by compression. This is taking longer time to arrive than the compression wave. The shear wave look taking longer time to arrive. I divided one another, square it, take one half minus one and use this equation, I can calculate for Sons ratio. And that is the way logs actually calculate for Sons ratio and then in a minute we'll see how you calculate the stress out of that. Because you run sonic log, you're getting density of the rock, so you can calculate the vertical stress, if you integrate the whole thing, you get the vertical stress. If I'm also doing Sonic-Log and I have to have enough distance between the transmission and the receiver, in order to be able to see able to see the compressional and shear wave distinctly from one"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "distance between the transmission and the receiver, in order to be able to see able to see the compressional and shear wave distinctly from one another. Once I get the Poisson's ratio, then I can get shear modulus. Here is a simple equation where A is a constant here, and from there I can calculate Young's modulus and you will be in business. So you can do it, you can do it with locks, okay? Or if you have velocity, here is the shear wave and the compression wave, the V sub V. So before we leave this area, okay, let's say I calculated Young's modulus and Poisson's ratio here from a log and I also calculated from any lab experiments, which is a static. So which one would I use? Are they equal? The first question, should we have an agreement? Should these two parameters, whether static or dynamic, be equal? Well, probably not. And there are two different types of measurements, one is static and one dynamic. And they will be different. Which one is larger depends on a lot of parameters."}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "two different types of measurements, one is static and one dynamic. And they will be different. Which one is larger depends on a lot of parameters. So we're not going to get into that, but which one would you use? Mostly we're going to say dynamic, and the answer is no, it is use static values in designing the fractures. Why is that? Well, the dynamic values is actually you are vibrating the grain, but what you, when you look at your fracture, although the fracture is obviously a dynamic process, but it is not depending on, on vibrating the grain, it's actually pushing the rock very much like what you do in experiment. And so, what most, what we would do is, you develop a relationship between the dynamic and the static properties in your formation. It's easier to, to run logs, you say, run the logs, you take the values and boom, through your correlation between static and dynamic you get the static and use that in designing the fracture. Okay? I may have said it a little fast, so you"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "your correlation between static and dynamic you get the static and use that in designing the fracture. Okay? I may have said it a little fast, so you may want to listen to the game. So here is the stresses, now, this area is a little dry I have to admit, but it's important to understand. So, now what stress would you use? Well, the stresses that you have, the total stress is carried by both the grains, sandy grains and by the fluid. grains, sandy grains and by the fluid. Okay, so the, the... and what is affecting the propagation or sanding or collapse of the rock, is the effective stress, not the total stress. Effective, because the stress is being carried by both the grains and by poor pressure. The first attempt to do that, to look at it, was Terzaki's effective stress. He said, hey, what is being carried by the grains is you just take the total stress and subtract out of it your poor pressure. However, people found out later on that poor pressure may not be 100% effective in"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "take the total stress and subtract out of it your poor pressure. However, people found out later on that poor pressure may not be 100% effective in carrying that stress. Because it moves out as you press it, it moves out. So, and you say, well, there is a factor here that is usually less than one one which will buy it coefficient. So rather than using assuming it's 100% efficient, we're totally efficient. So that's about constant anywhere between 0.7 to 1. It depends, most people will probably use about 0.9 or so. But, it is important to measure that parameters, especially if you're going to look at sanding. That is very important to do. So, you can see in some situation, your biotrch constant for Ottawa sand, prostate if it is dry is 0.33. You can see that's in megapascal. You wanna relate with mega, this is megapascal is 10 Atmosphere, so you multiply any of those numbers by about 145. One Atmosphere is 0.1 Mega Pascal. So, you can see there is, depending on the rock, it may be, it"}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "so you multiply any of those numbers by about 145. One Atmosphere is 0.1 Mega Pascal. So, you can see there is, depending on the rock, it may be, it may be up to 0.9 and in some rocks it may be down less than 0.5. So it's important to, to test the rock, you can only find it by testing. You test the rock and you find what, what batch constant, batch coefficient you... you have, because that's going to affect your sanding issue. So, we... we've done that, we... this is just a table to give you specific graph of different material, in case I... important, in case you get a problem on calculating that stress. So, fresh water is one, this is your specific gravity, is dimensionless. So, to get the... the stress down hold, is the depth, the integration of the depth time, times ... specific gravity time, point 433, which is ... the gradient of fresh water. So, in case of Quartz is about 2.65, 2.65 and so 0.433 times 2.65 it gives you whatever value is a little bit more than one psi per foot."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "water. So, in case of Quartz is about 2.65, 2.65 and so 0.433 times 2.65 it gives you whatever value is a little bit more than one psi per foot. Now without going into, hmm, I, let me look at the first equation. I usually, we go through the derivation of this equation, which is very easy to do. And I would, my advice is you go, if you Google it you'll find the derivation. Derivation is very simple. Basically all, all you're saying is that when we calculate Poisson's ratio, we are saying it's unconfined and we calculate how much lateral strain you have. But if that rock, where you are applying stress, is part of a huge formation, then it doesn't have room to expand. Then it's applying stress. So Poisson's ratio also is saying when I apply stress vertically, part of it is going to transfer horizontally. And so if I apply this concept, then I can say when I apply effective stress vertically, which is sigma V dash, there will be sigma H dash, there will be a horizontal stress, effective"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "I can say when I apply effective stress vertically, which is sigma V dash, there will be sigma H dash, there will be a horizontal stress, effective horizontal stress moving sideways. The relationship between the two is based on Poisson's ratio. Okay, so you can see Poisson's ratio has to be less than 0.5 because if Poisson's ratio is 0.5 that's saying the stress is transferred horizontally 100% that the rock cannot carry any stress which obviously that is false. So then the rock cannot carry any stress, which obviously that is false. So, if the rock can carry some stress, then Poisson's ratio has to be less than 0.5. In sandstone it may be 0.35 or so. So you can look at it as a 0.35 divided by 0.65. So it's a little bit more than half the effective vertical stress. Okay, in case of shale, if it's softer shale, it may be 0.4, a little higher than 0.4, not much higher. Sandstone, maybe even less than 0.35, maybe 0.3. So you can see that this is the reason that softer shale will have"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "higher than 0.4, not much higher. Sandstone, maybe even less than 0.35, maybe 0.3. So you can see that this is the reason that softer shale will have higher horizontal stress than hard rock, sandstone. And this, as we are going to talk about next week, this provide us with some confinement of hydraulic fracturing. So nature was nice to fracturing, to the oil industry, to create fractions that are somewhat confined. We'll talk more about that next week. And so here I'm just giving you this equation that I usually ask students to derive. You can see in the first equation is the relationship that very easy to derive. You may wanna Google it. I may add the derivation to the presentation that will put it in research gate. And we send you a link of the last week presentation. You're going to receive another link for this week's presentation. Then if I substitute the definition of the effective stress, I end getting here an equation relating the total horizontal stress to the total vertical"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "if I substitute the definition of the effective stress, I end getting here an equation relating the total horizontal stress to the total vertical stress, and obviously, pore pressure will appear, and also, Alpha will appear, if we're in class, I would have asked you if you remember what Alpha is, it is Biot's constant. In situ stress orientation is very important, there is multiple techniques to, to calculate it, that will... Let us wait till when we talk about testing next week. We... there's a lot of ways to, to do it. Next week we'll talk about the, the MicroFrac testing. I may, may add something, but I was not planning on it, but an Elastic Strain Relaxation, this is something, it's very interesting that we, we have done previously, we'll, we'll talk about it next week. ... we'll talk about it next week. ... I'll probably will not talk about tiltimeters, it's been used before, it's very interesting technique, but we may be able to... Then people will use well testing and doing it."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "about tiltimeters, it's been used before, it's very interesting technique, but we may be able to... Then people will use well testing and doing it. Geological rules of thumb, ... we... I have personally used that, we work with a company and the company was not, they really did not want to run any testing, say well can you guess what it would be from our geologic map, I looked at it and they said, yes, yeah we can do that. You, you look at it, it was an anticline, there was already long natural fractures, there was faults in the formation, so it would be parallel to the hydraulic fraction, most probably would be parallel to this fault, so you follow the anticline. And so that is one way of doing it. Let me look at the effect of drilling a well bore, because this is something I want to cover before we... I mean, it is fairly important to understand the breakdown of a well bore to create a fracture. So when you drill a well, to create a fracture. So when you drill a well, Oh, I, I could"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "the breakdown of a well bore to create a fracture. So when you drill a well, to create a fracture. So when you drill a well, Oh, I, I could have had a graph here. When I, drill a well bore, I, I change all the stresses around that well bore. Okay. Many years ago, this equation was developed, when I say many, I'm talking about more than a hundred years ago. You know, if you, if you know mathematics is, is more advanced than any other, other technology. People develop stuff in math that takes many years before it gets applied. So, if I have a rock, and let me show you, basically I did that by hand, couple of days in October, the weekend. If I, if I have, drill a wheelbarrow like this, and the minimum stress is this way, the, the minimum horizontal stress, the minimum, maximum horizontal stress is in the other way, and I'm looking at the top of the wheelbarrow. So, the vertical stress is going vertically into, into the picture. And, I'm going to look at an angle of Theta here. So, I, I"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "of the wheelbarrow. So, the vertical stress is going vertically into, into the picture. And, I'm going to look at an angle of Theta here. So, I, I can look at any point in the reservoir, not inside the wall bore. Any point inside this reservoir, this is my, the white area is my reservoir, and if I draw a straight line to the center of the wheelbarrow, I have this angle theta. So the stress at any point inside this reservoir is defined by these two equations. So Sigma RR is whatever stress that is going perpendicular going towards the center of the whirlpool. Sigma theta theta is the stress adjacent or tangential tangential to the wall bore or parallel to that wall bore. So you you can see it is moving like a circle around around this this wall bore. So this equation would describe so now you know the definition of Sigma H, Sigma H, Sigma H max, and the Theta. Rw is the Wilbur radius, and the R is whatever distance you are away from, from that Wilbur, from the center of the Wilbur. So"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "H max, and the Theta. Rw is the Wilbur radius, and the R is whatever distance you are away from, from that Wilbur, from the center of the Wilbur. So I'm going to do it just mentally here, rather than, usually it would be, I want you to, it may be a good exercise for you to, to eventually sit down with a piece of paper, I'm going to do it very quickly here. So the first question here is, what, what, what is Sigma RR at the wheelbore? Without looking at the equation. Well, Sigma rr at the wheelbore, if the wheelbore is stable, should be zero. So let us substitute here. So at the wheelbore, RW is equal R. So this is 1. 1 minus 1 is 0, so the first term disappears. And here was 1 minus 4 times 1 plus 3 times 1. So that is again 1 minus 4 plus 3. That is 0, so the second term is zero. So sigma RR at the well bore is zero regardless of theta. So that's now I have a stable well. If it is not a stable well, we'll find out later on, maybe next week we'll talk about testing, we'll see other"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "So that's now I have a stable well. If it is not a stable well, we'll find out later on, maybe next week we'll talk about testing, we'll see other situations. So Sigma R is regardless of Theta at the Wilbur it is zero. That sounds very good. So now let us look at Sigma Theta Theta which is tangential to the, to the wool board. So add, add the wool board, Rw squared divided by R, well R is equal to Rw, then this is, this is one, one plus one is two, two here cancels out, so I end up with sigma H plus sigma H max, minus this second term. I'm going to do it now for theta equals zero and theta equals 90 degrees. Okay, so everyone get a piece of paper and follow what I'm saying. So at R equal rw, so I have sigma h plus sigma h max minus, this is one plus three is four, then it becomes a minus, I'm going to open parentheses two sigma H minus two sigma H max. Time cosine, if I'm at zero, cosine zero is one. So when I put this all together, it ends being three sigma H max minus Sigma H min."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e133203c-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "two sigma H max. Time cosine, if I'm at zero, cosine zero is one. So when I put this all together, it ends being three sigma H max minus Sigma H min. Right? Okay now I'm going to do the same thing again except I'm going to put Theta of theta of pi over 2, 90 degrees. So pi over 2 times 2, that is, that's pi, that's 180 degrees. What is cosine 180 degrees? I hope you remember, it is minus one. So if I put, now multiply that second quantity by minus one, I will find out at 90 degrees, the equation is fairly similar, it is sigma, 3 sigma H min minus sigma H max. Okay? Remember that, because this equation, I will be asking you, if you know anything about hydraulic fraction, you remember the CFD definition and you remember this equation too. As well as the equation for Poisson's ratio, the relationship between the vertical and minimum horizontal stress. There's three equations you need to remember. So if I look in here, I find out the sigma RR at this theta equal to zero is three sigma H"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "stress. There's three equations you need to remember. So if I look in here, I find out the sigma RR at this theta equal to zero is three sigma H max minus sigma H min. And at 90 degrees, which is, would be vertical here, the sigma theta theta would be vertical. It is three sigma H Min minus Sigma H Max. Now if I'm ballooning, if I'm injecting fluid and I'm getting this well to expand, to get a little bigger, where would it break? It would break at this point where it has the smallest stress, because what I find out, that this would be the smallest stress here, and the high, talking about tangential stress, and this is the highest tangential stress there. So, fracture is going to break here and propagate perpendicular to minimum stress. Which it, that's the way it should happen. and propagate perpendicular to minimum stress. Which is, that's the way it should happen. I look at the bring down pressure and it looks something like that. So sigma RR at the whirlpool, regardless of where"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "the way it should happen. I look at the bring down pressure and it looks something like that. So sigma RR at the whirlpool, regardless of where you are, this is sigma RR, is zero. And when you go away, it goes back to the far field stress. Sigma theta theta depends on your orientation. So if I have a graph like this, which sometimes people call it hoop stress. So hoop stress, here is the largest, here is the smallest, so it depends, so if I'm ballooning the fracture it will break at the smallest value. There are a lot more to it because as you fracture the weld, you change the stress regime. So here I'm saying this is weld board that has not been fractured yet. So I apply stress, it should look something like this. If I increase the stress, eventually it will break at theta equal 90 degrees. It's in here, like what we show it's. So the fracture would propagate this way, perpendicular to minimum stress. How about breakdown? Have you ever looked at a formation and you notice it's"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "the fracture would propagate this way, perpendicular to minimum stress. How about breakdown? Have you ever looked at a formation and you notice it's breaking down? Well, when breakdown is under compression, so actually breakdown will happen in this orientation, because now I have very high maximum stress, it's causing the formation and lowering the pressure inside the wheel bore very much that you have a breakdown here and here. Then if I look at a breakdown I know immediately that the minimum stress is in the other direction. So, how to take care of it, is you increase the weight of the mud. And, here is the equation, considering the, the pore pressure, and the depletion of, of the formation. and the depletion of the formation. So here I have Wilbur pressure, and I have pore pressure, and obviously here you are be considering Biot's constant. So what equation you would remember, you want to remember, let's go back to this equation. You want to remember, not this whole equation, but"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e133226c-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "So what equation you would remember, you want to remember, let's go back to this equation. You want to remember, not this whole equation, but you wanna remember the three sigma max minus sigma h, because that appears very much. You wanna make it more accurate, you add the tensile stress to it, you wanna remember CFD, and you want to remember CFD, and you want to remember the whole sense ratio. So let us entertain a couple of questions. Again I'm going to put this presentation on Researchigate, we'll send you the link to Dr. Elgarhi, who will communicate with you, but you can, you don't actually even need the link, if you know what research you're getting, you can get on it and you can download anything you want, assuming it isn't there. I've sent also, Dr. Algarhia will send you a link to some write-up I did, it's a long time ago, in mid-90s, early to mid-90s, however it is still a very good writer. It's mostly for fractional, horizontal ones and I would suggest that you read it for"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e1332366-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "early to mid-90s, however it is still a very good writer. It's mostly for fractional, horizontal ones and I would suggest that you read it for your own enjoyment. Anyway, let's entertain a couple of questions. Okay, so thank you Dr. Solomon for this informative session. Now we will begin by addressing the questions. So the first question is that should we drill the horizontal wells in the direction of minimum horizontal stress direction and why? That's a good question. Actually drilling a well in the direction of minimum stress, we found out if you have normal stress regime, actually this is the most stable situation you've got. So second, we don't have, I don't have a presentation on that, well I do have in my computer but not in here. People always talk about what is the optimum or the best way to deplete a formation. You wanna drill horizontal well and fracture it usually in very tight formation. And the best way to do that in a tie formation is to create multiple fractures in that"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "well and fracture it usually in very tight formation. And the best way to do that in a tie formation is to create multiple fractures in that horizontal wells. If we look at history of what we have done, we all were the first who started, and the first fracture of the horizontal well was in late 80s. Actually, I do have a paper on the subject you can download from SPE that we, I wrote back and presented it in 88 and it was published in 1990. Well, I can't send you a link of it because SPE owns the copyright. So you have to download it from SBE. And so we used to talk about four to six wells. Now we fracture not even 10 or 20, sometimes a hundred fractures in one horizontal well because the formation is extremely tight. You can't, you can do that only with horizontal well, where you create multiple, multiple fractures. If we have time at the end, I will show you. Actually, I do have a nice presentation on, Actually I do have a nice presentation on, that I, we did eight, ten years ago. I"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: e1332492-8640-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "end, I will show you. Actually, I do have a nice presentation on, Actually I do have a nice presentation on, that I, we did eight, ten years ago. I may put it also in Researchgate, because it is my presentation. I cannot put papers, but I would put it in Researchgate, look at it, it's a very interesting presentation and it deals only with fracturing horizontal ones. And that usually, I used to cover it, it takes, it's only mostly about fluid flow and it used to take me about three hours to present but we put the presentation you may wanna you may wanna look at it. Okay great. Sometimes in the future we may present it to the group in the distant future. Go ahead. Okay, great, thank you. And, the second question is that, is it possible to see hydraulic fractures in real life? And, if yes, is there any real example for that? You see it real life? You see it in real life? Yes I think he means if it's visible, like to see it in the naked eye. No not visible. Horizontal. Let me say"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "it real life? You see it in real life? Yes I think he means if it's visible, like to see it in the naked eye. No not visible. Horizontal. Let me say something about that. We have, many years ago, when I was in the Halliburton company, we actually, Halliburton developed a tool. I was involved in it. There was a lot of people were involved in that specific tool. And it was a joint project between Halliburton and TUTAL. And, it was called the tool, T-H-E, for TUTAL-Halliburton extensometers. Basically, we worked on, myself and my group, we worked on the rock mechanics side of it, and those other groups worked on the electric, the electrical part, another group worked on the mechanical part. Where you go in, and you inject the fluid, and you balloon the well, so you, you don't observe it by eye, but you observe the behavior of ballooning of the fraction of the well bore and eventually you observe or measure the behavior of the fracturing process and the widening of the fracture. Dr."}


created_at: 2023-11-18 18:39:10
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "of the fraction of the well bore and eventually you observe or measure the behavior of the fracturing process and the widening of the fracture. Dr. Solomon, I believe that question mean instead of having vertical fracture, he's \u0645\u0646 \u0627\u0644\u062a\u062d\u0637\u064a\u0642. \u062f. \u0633\u0644\u064a\u0645\u0627\u0646 \u060c \u0623\u0639\u062a\u0642\u062f \u0623\u0646 \u0647\u0630\u0627 \u0627\u0644\u0633\u0624\u0627\u0644 \u064a\u0639\u0646\u064a \u0623\u0646\u0647 \u0628\u062f\u0644\u0627\u064b \u0645\u0646 \u0627\u0644\u062d\u0635\u0648\u0644 \u0639\u0644\u0649 \u062a\u062d\u0637\u064a\u0642 \u0627\u0644\u0648\u0636\u0639 \u0627\u0644\u0648\u0636\u0639\u064a \u060c \u064a\u062a\u062d\u062f\u062b \u0639\u0646 \u062a\u062d\u0637\u064a\u0642 \u0627\u0644\u0648\u0636\u0639 \u0627\u0644\u0648\u0636\u0639\u064a. \u0647\u0644 \u0647\u0630\u0627 \u062d\u0627\u0644 \u060c \u062d\u0627\u0644 \u062d\u0642\u064a\u0642\u064a \u060c \u0623\u0646 \u0646\u0631\u0649 \u062a\u062d\u0637\u064a\u0642 \u0627\u0644\u0648\u0636\u0639 \u0627\u0644\u0648\u0636\u0639\u064a \u0641\u064a \u0627\u0644\u062d\u064a\u0627\u0629 \u0627\u0644\u062d\u0642\u064a\u0642\u064a\u0629\u061f \u0647\u0644 \u0642\u0627\u0644 \u0623\u0646\u0647 \u062a\u062d\u0637\u064a\u0642 \u0627\u0644\u0648\u0636\u0639 \u0627\u0644\u0648\u0636\u0639\u064a\u061f \u0646\u0639\u0645 \u060c \u062a\u062d\u0637\u064a\u0642 \u0627\u0644\u0648\u0636\u0639 \u0627\u0644\u0648\u0636\u0639\u064a \u060c \u0646\u0639\u0645. \u062d\u0633\u0646\u0627\u064b \u060c \u0644\u0642\u062f \u0631\u0623\u064a\u062a \u060c \u0644\u0642\u062f \u0631\u0623\u064a\u062a \u062d\u0627\u0644\u0627\u062a Yes, horizontal fractures, yes. Well, I have seen cases, at least there was one very clear case where it was a horizontal fracture. I have another case that you don't, let's not say see, but observe the behavior of horizontal fracture. We've seen that. It's not very common, but observe the behavior of horizontal fractures. We've seen that. It's not very common, but we have seen it. Yes, it can be done in a vertical well, you see horizontal fractures. Okay, great. Thank you."}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "seen that. It's not very common, but we have seen it. Yes, it can be done in a vertical well, you see horizontal fractures. Okay, great. Thank you. And the last question for today, can we use the dynamic Young's modulus to design a hydraulic factoring operation or job without converting it to static Young's modulus? The answer is no. You need to convert it to the static values. There have been a lot of correlations. You have to build the correlation based on your reservoir. So many people have done that. You can't just, there is no, and also there is no general relationship between the two. It has to be developed for a reservoir. So thank you Dr. Salomon for joining us this afternoon and we are pleasure to have you today and I just want to highlight that this session was been recorded and it will be uploaded soon on Pio Petra's YouTube channel. And also for those who are considering to join this course, they already missed a quiz. However, they can still join, yet they should pass the"}


created_at: 2023-11-18 18:39:10
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 02-04.txt", "chroma:document": "And also for those who are considering to join this course, they already missed a quiz. However, they can still join, yet they should pass the three remaining quizzes and do the final exam. And for those who already joined, and please continue doing the quizzes and do the final exam. Now, best of luck. And thank you again again Dr. Solomon and have a nice day and see you in future webinars. Thank you. Alright. Bye everybody."}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "Hello everyone, I hope all of you are doing great and staying safe. On behalf of Biopetrol, Arab Oil and Gas Academy and SPE Egypt section, I'd like to welcome you to our third interesting webinar about hydraulic fracturing. This course consists of four webinars, four quizzes and the final exam. First, let me introduce myself. My name is Selma Rashidi. I'm a petroleum engineer. I owned my bachelor's degree from the American University of Ras al-Khaimah. And my name is Shahad Bajet. I'm a third-year petroleum engineering student at KNU in Kurdistan, Iraq. And we will be your moderators for today. Our lecture today will be delivered by a very special guest from the University of Houston. Professor Mohamed Salman is the chairman of the Petroleum Engineering Department. He holds 35 patents on hydraulic fracturing operations, analysis, testing, and confirmance applications. He is the author or co-author of over 250 technical papers and articles in petroleum engineering. Professor Solomon"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "and confirmance applications. He is the author or co-author of over 250 technical papers and articles in petroleum engineering. Professor Solomon is a registered professional engineer in the state of Texas. He is also a well-known member of the Society of Petroleum Engineers and the National Academy of Inventors. He has authored several book chapters on stimulation testing. Also, Professor Solomon is the primary editor of Fracturing Horizontal Wells, published by McRaw Hill in 2016. He's a co-author of Optimization of Hydraulic Fracture Stages and Sequences in Unconventional Formations, published by CRC in 2018. Professor Solomon holds a bachelor's degree with honors from Cairo University, the mic is yours. Thank you very much. Welcome everyone. Hope you enjoy the lectures. Uh Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Yeah. Thank you very much. Welcome everyone. I hope you enjoyed the lecture. This lecture will talk a little bit about fracture design. We'll address several"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "you very much. Welcome everyone. I hope you enjoyed the lecture. This lecture will talk a little bit about fracture design. We'll address several issues that we have in fracturing. I hope you enjoy it. that we, we have in, in fracturing. I hope you enjoy it. And if you have questions at the end, we'll try to address a few questions, but you can always send other questions to me on my email, which it would be mysolomonatuh.edu. If we run a fracturing treatment, this is, was basically a test, which we ran a very small fracturing treatment, but it shows what, what usually happens. In this specific case that we ran many, we ran it many years ago, where ... where we had downhole gauge, and we monitored the pressure rate, and we also monitored ... propent if we, if we have some. ... So you, you can see here, you, like what we talked yesterday, and I'm going to show another slide that even shows that even more clearly. ... As you inject, as you inject the fluid, you can see if I have"}


created_at: 2023-11-18 18:45:36
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "and I'm going to show another slide that even shows that even more clearly. ... As you inject, as you inject the fluid, you can see if I have injection rate, I have down hole pressure. ... As I inject, the pressure will increase at one point, I'll ... break down the formation. If you, if you attended last week, and we talked about it, there is a breakdown, that we, if you remember, we looked at the equation, I ask you to, maybe go through the derivation a little bit. It is ... 3 Sigma H H min minus sigma H max. And the fracture is perpendicular to minimum stress. And you can see it, once you bring down the wellbore, the formation, pressure will decline, then it should stay constant or increase a little bit. We'll talk about that a little bit more in this lecture. Most of the models we see some increase in bottom hole pressure that has... people use it in analysis, we'll discuss that. ... but, that would be indication of fracture propagation, you can see I have a slurry rate here, I"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "people use it in analysis, we'll discuss that. ... but, that would be indication of fracture propagation, you can see I have a slurry rate here, I have... ... there is not much of problem to concentration, this is mostly like a test. And, you can see at one point I'm going to shut down, stop injection, ... pressure would decline, the sharp decline in pressure, we'll, we'll see more exaggerated case in a minute. ... That will be an indication of near wall bore ... friction ... inside. With the, with down hole gauge, that's what I'm going to see, the near wall bore friction. If I'm having surface gauge, then I see sharper decline, which will indicate the, the friction inside the, the tubing. Or ... or, or whatever ... inside the tubing, or ... or whatever inside the wall board, going from surface down to down hole. And once I... we stop, there is some pressure decline, we'll... Next ... next week we'll talk about analysis, very much analysis of this area here, what happens when you stop"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "is some pressure decline, we'll... Next ... next week we'll talk about analysis, very much analysis of this area here, what happens when you stop injection and the pressure will decline, that will cover it in fracture testing. This is another, another case that we, we looked at, and you can see sometimes people either they monitor like this orange line, the tubing pressure, this is the surface pressure, or you monitor ... down hole pressure. So there is a lot of things that one will monitor during fractioning treatment, and it is not monitored for no reason. We are going to see, as we talk about today and the next week, a lot of this data need to be analyzed, people analyze it. I'm not sure, some of it is real time, some of it is after the fact. We'll see how we do that. Okay, this is, was a test and which run many, many years ago. Actually I was on that job. It is, it's interesting. It's what we call micro-FRAC. I'm going to discuss it more in detail what micro-FRAC is later on. But"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "I was on that job. It is, it's interesting. It's what we call micro-FRAC. I'm going to discuss it more in detail what micro-FRAC is later on. But the reason I'm showing you this slide is to show a very controlled test. You can look here, I have injection rate showing here, I'm injecting, I'm shutting in, injecting, shutting and so on. So I actually have fractured this wellbore three times. The very first time, you can see pressure increased very much, and at one point, the... here we see very sharp drop in pressure. Actually, this point here, this sharp point, is where you broke down the formation. That is the breakdown. Once you break it down, this sharp resistance, the hoop stress we talked about last week, you can see here once I overcome that hoop stress, pressure will decline very much. So there is a drop here. One make, you know, some people have taken this value and say, well, if I know minimum stress, I can also calculate maximum horizontal stress from here. Sometimes it"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "some people have taken this value and say, well, if I know minimum stress, I can also calculate maximum horizontal stress from here. Sometimes it works. So here I'm injecting, so there is some propagation, and then at one point I'm shutting down. So you go from here to here, very sharp with decline. Eventually you lose pressure inside the fracture and the fracture will close. And so, one will ... can use data here from the shut-in down to fracture closure, and from fracture closure down you can do some other analysis. So that will be before the closure analysis, this is the after closure analysis, we'll discuss it a little bit next week. The fracture closure pressure is very important value, and the reason for that, if, if, if we're running a test, and the amount of fluid that we're injecting is fairly small, that closure pressure will be very close to the minimum in situ stress. You know, the far field distress we talked about last week. So what happens now if I come back, if I come"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "very close to the minimum in situ stress. You know, the far field distress we talked about last week. So what happens now if I come back, if I come back and I, after some time, I start injecting again, would I see that breakdown? Of course not, because you can break down the formation. And this is a vertical one. You can break it down only once. So when I start injecting again, at one point I'm going to reopen that fracture again. So I'm reopening the fracture. Opening the fracture is a lot smaller than the reopening pressure is a lot smaller of course than the breakdown pressure. Because here I'm just overcoming the minimum stress in the breakdown pressure, overcoming the hoop stress which would be 3 sigma min minus sigma max. So here I'm doing, we did the same thing so we repeated the test a couple of more times. And we wanted to see whether I have consistency in fracture closure pressure, what we did, we had consistency of ... ice IP, that's near, near fracture, fracture pressure."}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "I have consistency in fracture closure pressure, what we did, we had consistency of ... ice IP, that's near, near fracture, fracture pressure. fracture ... fraction pressure. And another issue I want you to... we're not going to... we're going to... it's going to affect what we do in testing, but you need to know a little bit about it, because this is a very famous equation that was developed many years ago, people call it Carter's equation. Basically showing ... as you're injecting fluid inside the fracture, you expect a couple of things, you expect the fracture is propagating, so there is some fluid staying inside the fracture otherwise it would not be opening, so I have fracture volume, but I have some fluid that is leaking off. And that, that fluid that's leaking off, I'm going to call it leak off volume. ... In many of the experiments we do in the lab, to determine how much fluid would leak off, we do in the lab to determine how much fluid would leak off, would eventually it"}


created_at: 2023-11-18 18:45:36
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "we do in the lab, to determine how much fluid would leak off, we do in the lab to determine how much fluid would leak off, would eventually it follows a shape like this curve. Basically linear fluid, there is some early fluid, fluid that will leak off very fast. I call that a spurt loss. So that as soon as the version of formation gets exposed to a high pressure fraction fluid, I'm going to see, I'm going to see fluid leaking off very quickly, more or less instantaneously, I call that a spurt loss, and then it follows a straight line, that I'm plotting versus square root of time, and the slope of that straight line is my Lekhov coefficient. If you remember in the first week we talked, two weeks ago, we talked about linear flow being, always shows itself as a square root of time. You may not remember that, but let us repeat it here. So usually when you have linear flow, it is linear function of the square root of time. If you remember when we talked about infinitely conductive"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "So usually when you have linear flow, it is linear function of the square root of time. If you remember when we talked about infinitely conductive fracture. So however in many of development of analysis like in testing, since the spirit loss is small, they approximate the whole thing with a straight line going through zero. So there is some more extra work that one may do. We actually published some work in the area where rather than assuming the spirit loss is too small, we actually consider the value to it. It's kind of an interesting solution. But we have developed in the industry so many new solutions. Now, where we, rather than using leak-off coefficient, we depend on fracture permeability and say, well, this is dependent also on fracture permeability, and one can develop solutions for that. We'll talk about some of those solutions next week. With a fracture you... I'm going to give you just a little bit of ... what is ... equation that people will use in simulating fracture and"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "next week. With a fracture you... I'm going to give you just a little bit of ... what is ... equation that people will use in simulating fracture and solving those equations. Basically, most people will assume that the pressure inside the fracture is constant. So there is not much of a pressure blow inside the fracture during compression. So that's except near the tip. Near the tip of the fracture, the pressure gets very narrow. And so many of the solution we'll talk about today will have this assumption here, saying the width of the fracture is function of E prime. E prime, I defined it here, is the plane of the modulus, which would be equal to Young's modulus divided by one minus the square of Poisson's ratio. So if Poisson's ratio is 0.3, so square is 0.09, so it is Young's modulus divided by 0.91, if it's 0.3. One, one important parameter that you, people look at, is stress intensity factor, which is nothing but the pressure inside the fracture, times the square root of length,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "that you, people look at, is stress intensity factor, which is nothing but the pressure inside the fracture, times the square root of length, the fracture length. And you, usually this term, people look at it as, Psi per square root of inch, not foot. So you can see when the fraction is very, very short, just starting, this value may be fairly, fairly small. Once the fraction length gets a little long, this value gets really large. Why I'm talking about it? Because this value needs to be greater than, than KIC. KIC is a critical in stress intensity factor or you call it fracture toughness, toughness which is function of the formation. So let us look at what values we have for formation for this KIC. It is sandstone is maybe 1200 to 1500. So you know if your pressure inside your fracture is of any significance, once it becomes a couple of feet, the fracture length is couple of feet, it will be, the KIC doesn't come into play anymore. It's not that important. Which it, when you think"}


created_at: 2023-11-18 18:45:36
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "of feet, the fracture length is couple of feet, it will be, the KIC doesn't come into play anymore. It's not that important. Which it, when you think about it, if once you, you can see if you hold a piece of say wood and it has a little crack and you try to extend that crack, if it's very short it is very difficult to extend it. Once it gets along, you know, your the pressure time length becomes so high that you can overcome the resistance, the fracture toughness of, of the formation. You can see here, sandstone to 1,400 to 1,500, shale maybe a little smaller, granite is, is fairly high. One would, one would say, why do you worry about granite? Actually, there is a lot of new work being done on Granite, including here at University of Houston, but that is a research subject we can talk about some other time. One thing, when we talk about plane strain, many of your... is 2D and pseudo-3 models, we'll talk about plane strain. We're assuming that whatever happens, if I have fracture,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "plane strain, many of your... is 2D and pseudo-3 models, we'll talk about plane strain. We're assuming that whatever happens, if I have fracture, whatever happens, all the strain remains in this plane. When I deal with pseudo 3D models, I have a couple of slides at the end comparing the two. When I deal with full 3D model, now I'm going to say every place, everywhere inside the formation will have an effect on the fracture everywhere. So that it becomes a lot more sophisticated and more difficult to solve. At UH as well as in other places, everyone that developed his own models basically for research and we did the same. So if we deal with plane strain, which is very good in explaining a lot of things and we use it in data analysis, simplifies things and what it also gives a very good results. So, we're saying all the stress and the resulting strain remain on a plane which can be repeated infinite times. So every plane is by itself. And you can look at it either in vertically or"}


created_at: 2023-11-18 18:45:36
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "resulting strain remain on a plane which can be repeated infinite times. So every plane is by itself. And you can look at it either in vertically or horizontally. If you look at it in a vertical, vertical plane strain, and then the model that was developed years ago for that 2D model, which we are going to use in analysis of data is Perkins and the Kernel model, the PKM. And the horizontal plane is KGT, KGD is after, is, we used to call it Krasnovich and Zoltov model, the original name. That's saying I'll do it in the horizontal plane. There is evidence that PKN works better, and I'm going to explain why I, that's my own personal opinion. Of course, other people may disagree with it, but I'll tell you why I think this is the case. So if I, if I look at the basic PKN, in a regular class we'll go through modeling and writing equations and maybe software for it. For PKN, I'm going to assume that the fracture cross-section is elliptical and as it is constant, the height more or less,"}


created_at: 2023-11-18 18:45:36
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "and maybe software for it. For PKN, I'm going to assume that the fracture cross-section is elliptical and as it is constant, the height more or less, although we allow that to change, and is elliptical in the horizontal direction. And from there I can write an equation for width and I can write equation for pressure. And equation for pressure is going to show that, that was PKM model. Pressure, if I don't have sharp increase in heights or changes, serious changes, in most models, when you see some increase in pressure was time. A KGD assumes that I have a rectangular shaped cross-section, essentially saying we have a slippage on the boundary and that will reflect into constant pressure or even declining pressure. In most cases, in field cases, we have seen that the pressure does, when you have a successful job, pressure does increase with time a little bit, in some slope. We'll get into that slope in just a few minutes. I will tell you it's between, no, I need to wait till, because I"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "time a little bit, in some slope. We'll get into that slope in just a few minutes. I will tell you it's between, no, I need to wait till, because I need to talk more about it and see what we plot there to see that pressure increase. In those cases, we're looking at fracture height and fracture height prediction. Is containment important? Yes, it is important. I'm going to show you some experiments that we have done in the lab before. Is it critical? Absolutely. You can, if you don't watch for it, you don't want to fracture into water. If you end fractures, say propagating downward and the fracture into, into water like some of the shale formation in North, in Northern US, United States. You know, you watch very much for fracture height because you have water zones below. And if you fracture into water, you essentially have a water well. So you want to control it. And it's not only that you get too much water, but you waste the prop and the fluid. Can it be controlled passively? Was"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "So you want to control it. And it's not only that you get too much water, but you waste the prop and the fluid. Can it be controlled passively? Was that has been usually successful by looking at the injection pressure and monitoring what the pressure you're injecting. You may be monitoring the job. There is some ways to do that. We'll talk about some of them. But, but that's in a passive way, so I don't want to exceed certain pressure, so I don't break into, into another zone. ... Some people have tried it actively, ... using say, if, if you have downhole, you have a zone below your pay zone, that is, that, ... that is ... maybe carrying water and you don't wanna get into it, for water or whatever other reason. You could, some people have used the heavier propant. So they say, well, the heavier propant will settle and will prevent the fracture from, you end up having very high friction pressure in order to propagate that fracture. So you, it prevents a further propagation into the"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "fracture from, you end up having very high friction pressure in order to propagate that fracture. So you, it prevents a further propagation into the lower zone. People have done it by creating a fracture with propant and then going back, perforating above into the pay zone and doing the, the fracturing, so it, it may work okay. There is ... the success of those active using Propant is, is not completely proven. Passively, yes it's proven by, especially when you monitor what is going on, using temperature, maybe pressure to know where, whether you're propagating down or not. You go, propagating downward or not. The containment happens due to one of, the natural containment happens because if you have a stress contrast, if you have a change in lithology. Let us show some slides, some experiments that we did several years ago on that subject. First, to stresses, it's very important to, in in advance to calculate the stress, both in, both in various layers and ... to calculate or measure"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e1150c-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "First, to stresses, it's very important to, in in advance to calculate the stress, both in, both in various layers and ... to calculate or measure the, the stress in your pay zone, above the pay zone and below the pay zone. ... If, many time the stress variation is just due to variation in Poisson's ratio. If you don't have lithology change, but it can be due to just change in Poisson's ratio. If you remember, we talked about this upper equation here, and this is the effective stress in horizontal direction is Poisson's ratio or one minus Poisson's ratio times the effective vertical stress. If I substitute the definition of effective stress with bar its ratio, I decided to, I did not write it as a slide here, but I, I did a little bit of calculation, saying okay, and maybe you should give you this as a homework assignment. If, if you have sandstone and Poisson's ratio is 0.25, if I have 6,000 foot formation, I, I could end calculating my, my horizontal stress if I assume one piece I"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "sandstone and Poisson's ratio is 0.25, if I have 6,000 foot formation, I, I could end calculating my, my horizontal stress if I assume one piece I for, for, for vertical stress, for total vertical stress and you substitute all the, but constant and pull pressure, we say pull, pull, pull pressure is gradient, say of ... here I said of 0.4, I end calculating ... vertical stress of 6,000 PSI, horizontal stress of 3,000 PSI, horizontal stress of 3,600 PSI. But, if I... if this ... Phase Zone is surrounded by... by shale, that's softer, and ... let's say for size ratio, in this case is 0.4, then my horizontal stress would be calculated at 4,800 psi. That is 1,100 psi stress contrast between the P zone and the shale zone. And if you have something like this, that will be sufficient to confine the fracture. So let's look at, oh, here is the problem. You will have it, you can solve it and see whether I made a mistake in my calculations or not. But here, here what I'm trying to show, if I have"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e115d4-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "You will have it, you can solve it and see whether I made a mistake in my calculations or not. But here, here what I'm trying to show, if I have soft shale around the pay zone, sandstone reservoir, it may be confined. Well let us see if we, if it's really confined or not, because we have to talk about theory. Here is an experiment that we ran several years ago. This was a piece of rock that was 18 inch in length. It was 12 inch in height here, and the thickness was six inch. And we created a well in the middle, we had a perforation like you see here, I hope you see my mouse, my around the mouse, you can see here, I have, I perforated or have this an open area, and the rest is closed, I have a I perforated or have this an open area, and the rest is closed. I have a pipe here, and I started injecting, and you can see I created, very much, the fracture that I have here. The reason for that is I've got, basically I did not stress in the middle here, and I put 1200 PSI above and below. So"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "the fracture that I have here. The reason for that is I've got, basically I did not stress in the middle here, and I put 1200 PSI above and below. So I have a stress contrast of 1200 PSI, that was sufficient to confine the fracture, although the formation is homogeneous, and there's absolutely no change in lithology between the middle part and the upper, upper and lower parts of the back. This is with the same piece of rug, the only difference is the stress. So we applied vertical stress of 1400 psi, I applied side stress here of 2000 psi, of 2000 PSI and then the stress perpendicular to the, to the screen is zero in the middle 1200 above 1200 below. So those are the lowest stress, so I'm expecting a fraction that will propagate along the screen. And you can see here, if you look carefully in it, and hopefully you can see it, you can see that it's, it looks like, almost like lines in here, like streamlines, where the fluid is going in and opening up this fracture. Experiment looks"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "see that it's, it looks like, almost like lines in here, like streamlines, where the fluid is going in and opening up this fracture. Experiment looks really impressive. Well, in the other case, if I have negative stress contrast, if I have negative stress contrast, if I have negative stress contrast, if I, if I say okay maybe I have sandstone here, I have shale, maybe I have water, although I may have a barrier here, but below that shale I've got loose, loose stress formation and, and I don't want to get into it, but we did not realize that, so we fractured it anyway. So, this is a similar case, a similar size rock, and you can see here, the smallest stress, or smallest stresses are the one, perpendicular to the, to, to the screen. And you can, you can look here. This is just a highlighter. And you can see it basically to compare the size. This is 18 inches again, and 18 by 12 by six inches in thickness. And here we're doing it in a fraction in the middle. So I have 600, 1000 PSI,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "size. This is 18 inches again, and 18 by 12 by six inches in thickness. And here we're doing it in a fraction in the middle. So I have 600, 1000 PSI, 1000 PSI and I have here zero stress. So what happens here, when I, when I fracture in the 600 PSI, initially if you, if you see that same piece of rock, fracture propagated very much like what you would expect, but once it's so the low stress, you can see the propagation went down hole. So, so went downwards, and boom, all you can see much of the propagation went to the lower stress. So one has to be very careful. So knowledge of stresses is, is not just something that theoretical thing you need to do. It is really practical thing to do. This is the reason people have been, have been measuring and calculating stresses. We talked about calculating stresses from logs, like what we, the equation we saw. We're going to talk about measuring stress. Well, part of it, that fracture closure pressure, if I don't inject very much of fluid and I"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e117fa-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "we saw. We're going to talk about measuring stress. Well, part of it, that fracture closure pressure, if I don't inject very much of fluid and I monitor the pressure carefully, I will see the fracture closure pressure. It's a very important parameter. We are doing a lot of research in the area right now. Believe it or not, it's still not, not a, is still open for interpretation. So we have our own technique, we may mention it a little bit, this is more of a research area, but we have companies really believe in what we're doing. So there is still a lot of work to be done in the area, nothing is final, science and technology never stop. But the important thing about this slide, you can see here, it went down all your much of or most of your, or your propagation is happening in the lower stress zone, and it ended breaking even into that lower, the stress, this lower, higher stress zone. stress, this lower, higher stress zone. So what is the problem with that? The problem with that is"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11868-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "lower, the stress, this lower, higher stress zone. stress, this lower, higher stress zone. So what is the problem with that? The problem with that is your perforation are up here, your problem to may be sitting all down here. So you may not have communication even if this zone is is productive, there is no communication with the perforation. It is worse if this formation is having water or having issues, or so you're wasting a lot of energy, a lot of money, your province, your fluid, to get a fracture that is not effective. So you fracture it and say, oh, I am not producing nearly as much as I expected. Well, maybe because the fracture went in the wrong direction. I saw the opposite too. This was not in the slide, but I saw the opposite too, where we've been involved in a case for, can't tell you the oil company, but here in a smaller oil company in United States, several years ago, where they fractured and most of the fluid it came from a layer that they did not know was productive."}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "company in United States, several years ago, where they fractured and most of the fluid it came from a layer that they did not know was productive. And the reason for that is the fracture propagated upward and intersected that formation that they were not intending to fracture at the end. Luckily for them, they ended getting a lot more production than they expected. But, still that's not right, because you... one has to know in advance, you need to make at least ... some knowledge of what is going on, so you design the best diffraction treatment possible. Well, if you, if you have some lithology change, you could have problems too. So a situation like this, where, where there is a fracture that's propagated upward and it ended big since I have a barrier here and that's not very strong and the fracture although there is some breakage through it but most of the propagation went sideways so that's again another another issue. This is more of discontinuity. We have seen that of"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "through it but most of the propagation went sideways so that's again another another issue. This is more of discontinuity. We have seen that of discontinuity. We have seen that, actually, I have a case that we wrote a paper on several years ago. If you're interested in it, we had the logs, we had everything, and we ran very nice design, and we said, okay, we'll go apply it in the field. And after we applied it, we found out the fracture height, actually the fracture was better than expected. So we go back and measure it and the fracture height was smaller and eventually we realized that the logs did not show some break in lithology. So once you have a break in lithology, that can be a barrier. So you end to have confined fracture. So this is something again, we did not know. There is, people have seen, especially in shallower formation, this from paper by Warpansky. It was a fairly shallow formation that they went back and mined back the formation. You see there is multiple fractures."}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11a02-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "from paper by Warpansky. It was a fairly shallow formation that they went back and mined back the formation. You see there is multiple fractures. Part of it, this can be misleading a little bit because it was formation was a little bit too shallow to have the stresses that basically overcome heterogeneities in the formation. So the fracture followed the heterogeneities. You see things like this when you fracture shears because of the natural fractures you end up opening those natural fractures and they have very significant effect on what is going on. opening those natural fractures, and they have very significant effect on, on ... on what is going on. We are going to see some cases, real cases, actually with deep formation here in United States, Shield formation that we, we analyzed using some technique that we have developed. This is ... multiple fractures, they were actually, this also from Morpensky's paper, but there was a recent paper, couple of years ago, by ConocoPhillips,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11aa2-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "... multiple fractures, they were actually, this also from Morpensky's paper, but there was a recent paper, couple of years ago, by ConocoPhillips, where they did something similar, but except they did not, they did not mine back the... the well, because that was too deep to do that. Here we're talking about a few couple of hundred feet. But in ConocoPhillips' situation it was a very deep formation and they did not find problem in where they thought you would have problems. So, the fracture propagated in multiple... we have multiple fractures in multiple areas. It was a horizontal one, this one here, it was a vertical one in this example. ... You can see here also, you can see the fracture propagation, it looks like jumped, obviously it went around here, and then there's another crack. So there is discontinuity in the fracture. And, any time, any time you have turning of fracture, that's usually not good news, because it have very high friction pressure, and the turning around of"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11b38-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "any time, any time you have turning of fracture, that's usually not good news, because it have very high friction pressure, and the turning around of fracture happens on steps. the turning around of fracture happens on steps. So it does not happen very smoothly and that you would have a narrow, very narrow effective fracture width, which usually can, can cause sand out. The sand out meaning that the sand cannot continue to move, it's friction pressure is so high, that basically, eventually you have to shut down the treatment. So, here I'm going to give you some equations that were published in literature. There's so many different equations looking at things like that. And so, here if I have stresses, you can, you can, you can see, if fraction is propagating through higher stress, it may give you a pinch point, it may go up and, if I get higher stress here and we have, there'll be an upper tip and lower tip and with a pinch point. So let's look at, what would it would take to"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11bd8-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "if I get higher stress here and we have, there'll be an upper tip and lower tip and with a pinch point. So let's look at, what would it would take to propagate a fracture. Usually we do it numerically. There is a lot of simulators in commercial as well as research simulators for fraction propagation. But sometimes it is good to look at cases where you have an analytical solution and you can look at it yourself in case you wanna do something very quick. So in a situation where this is symmetric case, I have a zone like this, a P zone like this, and surrounded by the higher stress. And here, since it's symmetric, I'm going to assume Sigma 2 and Sigma 2 here, they are same value, same rock. And I, I have this P-Zone in the middle. So the, if this is the case, if I ignore the, the effect of height, there is a little difference in height, so nothing is really, truly, truly symmetric. Because even if, even if I, if the stresses are the same, there is Hydrostatic head that is different. But"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11c78-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "nothing is really, truly, truly symmetric. Because even if, even if I, if the stresses are the same, there is Hydrostatic head that is different. But here I'm going to ignore this effect, and say fracture propagates upward and downward, as similarly. So I end having a single, the, the pressure, I can calculate the pressure that I need to, in order to fracture this formation. This pressure is related to the stresses that I, I have above and below and in the P-zone. So, since it is symmetric, Sigma 2, Sigma 2 here, pressure Sigma 1, and you can write this equation. I usually give a problem in this, for people to see what happens when the fraction height is very large. Once it gets very large, the effect of KIC becomes very small. And so, this confirms what, what we talked about earlier in this lecture. If it's a height, as when height is very small and then you, and then KIC becomes important. So the important of the second term, it gets smaller and smaller with time. There was, there"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11d18-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "very small and then you, and then KIC becomes important. So the important of the second term, it gets smaller and smaller with time. There was, there was fractional propagation and height, eventually it, it becomes essentially negligible. If you use this equation, please remember, when you write something like this, you know, it is not in degrees, it's in radium. How many, I've seen students that put this, get the angle and write it in degrees and say well the answer doesn't make any sense, of course it doesn't make sense because this should be in radium not degrees. If I have a case that's not symmetric it gets a little bit more complicated because the propagation in height above and below is different. Basically the center of the fracture moves in this case upward because the upper layer stress is smaller so I'm expecting more fraction propagation in upper zone than the lower zone. So you end this equation and you I'm just writing this equation for your knowledge, that's something"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11db8-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "propagation in upper zone than the lower zone. So you end this equation and you I'm just writing this equation for your knowledge, that's something to choose but you are going to find many equations like this in ... in literature. So, here if I have non-symmetric case, even if KIC is all the same, 1000 psi per square inch, you can see that the center of the fracture is moving upward. It can move actually upward above even the ... the P zone, depending on stresses, depending on your treating pressure, and those time. So, let's look at the material balance variable. This is the variable here, I'm injecting, you have fluid leak off, it's widening, the fracture, and I want to look at this, in general, and say, say well what happens, how we can analyze data. There was a paper that was written, a bunch of papers were written, but there is one were written by Nolte Smith that we are going to depend very much on the first part on this analysis, then we'll talk about a paper that ... myself"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11e4e-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "were written by Nolte Smith that we are going to depend very much on the first part on this analysis, then we'll talk about a paper that ... myself and my students, actually multiple papers that we wrote on, on the subject. Most people don't realize that many of the models will depend, and the analysis techniques will, during fractional propagation, will depend on what is called the power law assumption. Basically it is saying, fraction length and the hidden area, we're writing in terms of area, but if you assume that the height does not change very much, then, then the length is, is fraction of time raised to some power. is function of time raised to some power. So, if I, if I take this concept, and going into treating pressure analysis, and I need to refer you to paper by Nolte, by Nolte and Smith, that was published several years ago. I, I should have written the paper number. I thought I did. I'm sorry, I, I let me see. I did not write it. I, I apologize for that, but I think we"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11eda-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "I, I should have written the paper number. I thought I did. I'm sorry, I, I let me see. I did not write it. I, I apologize for that, but I think we need to... I'm going to modify the presentation before putting it in, into Researchgate to have that SPA number, because this is, this is, it's not just to, to make sure that I'm referring to the right place, but also it is, it interesting for you if you wanna, wanna pursue the subject to read that paper. It's very fundamental paper by Nolte-Smith and it was published long time ago, but it is really an excellent paper. Basically, they, they said, okay if I plot the net pressure, net pressure is the pressure you're observing, the down hold pressure minus, minus closure pressure, or minimum in-situ stress. If I plot that net pressure, and you, you please notice when I say net pressure, that's a pressure difference, from minimum in-situ stress, not poor pressure. People that are doing well testing the Delta P is from poor pressure. So here,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e11f84-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "a pressure difference, from minimum in-situ stress, not poor pressure. People that are doing well testing the Delta P is from poor pressure. So here, my down-hole treating pressure minus minimum in-situ stress, if I take the log of this value and plot it log of time, they said, hey we can get one of various modes, and they called it one, two, three, four. Okay. Let's look at this modes. Mode one, which I see pressure going, maybe between 0.2 to 0.35, although I'm writing what they wrote, but I think it's usually a little higher than, than that. So, if I get slope like that, that tells me that the fraction is propagating normally, because that's what I expect to see from that power law model. to see from that power law model. If everything is okay, I'm going to see about 0.2, 0.25, 0.3, 0.35, you know, in that range, that will tell me that the fracture is basically a fairly confined, so I have some containment. There may be obviously some fractional height growth, but it cannot be"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "that the fracture is basically a fairly confined, so I have some containment. There may be obviously some fractional height growth, but it cannot be excessive at all, and so, so that what you would hope to see throughout a fractional treatment, obviously, because now you see a nice fraction is propagating, you're getting a lot of length. Okay. Then they looked at model two, and they said uncontrolled fractional height growth. That's what I'm going to differ from them later on and what you're going to see in a minute. And they said, now you have an issue, and many times it may be natural fractures and you may, may it end turning into model, mode four, where you say, okay, my mode four is, let me go to mode 4, pressure is declining, I added this intersecting or opening natural fracture, breaking out of zone, lower extension pressure. Actually in their paper, if you read their paper, model 2, they had an issue of explaining model two, we have a different way of doing it right now. Then"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "in their paper, if you read their paper, model 2, they had an issue of explaining model two, we have a different way of doing it right now. Then model three, nobody disagrees with that, is saying, if I see a very sharp pressure increase where it goes to slow one to one, that is usually a screen out. So one-to-one, that is usually screen out. And so you better be ready to stop injection. So that's tell me that the fracture is ballooning, is getting wider rather than getting longer in length. Sometimes you see cases where it is even going higher, the slope is higher than one to one. Okay, so we look at that and we, there was some recent decline in use of this model because there is a model, mode one and model three, there's really no disagreement in them. Two and four were some problems. So we developed our own new technique. So here I'm referring Maltesmith technique. The one issue that we had with it is the reference point is all based on zero time, which is a start of injection. We"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "referring Maltesmith technique. The one issue that we had with it is the reference point is all based on zero time, which is a start of injection. We look at some experiment that we have done in the lab and some observation in the field and we think that fracture does not continue propagating. And once it stops propagating everything as if it's the time is reset. So we say the process that's in the technique we developed when the the process is this discontinuous. So we build another approach. I'm going to go through it a little quick because it's mostly research area or very recent area, but I encourage you to read the papers. We wrote a few papers on the subject. So very interesting. papers, we wrote a few papers on the subject, very interesting. So here I took a case and we applied Nolte-Smith analysis and this is taken from this paper here and this paper will give you a reference to Nolte-mith. I should have done it anyway. Sorry for that. And it looked at something like this. And"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "here and this paper will give you a reference to Nolte-mith. I should have done it anyway. Sorry for that. And it looked at something like this. And when you look at it, the early part looks okay, but then you can see now it's going, the net pressure, this is log-log graph. The net pressure is flat, but if you are analyzing the data, you say, well, I'm not going to do anything. Well, I do not know what is going on. And then you get in here, you have to wait till this is 10, 20, 30 minutes. This is what people call frack pack. This is fracturing high permeability formation in the Gulf of Mexico. And we got it from a company that did that work. And so, but we can, all I can tell you is in Gulf of Mexico. So basically they waited, this is 30, 40, after 40 minutes of injection, usually those runs are usually fairly small. You stop. So we analyze it using our technique. Our technique is saying, every time there is some changes, I reset everything. I reset the reference point. So we call it"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "it using our technique. Our technique is saying, every time there is some changes, I reset everything. I reset the reference point. So we call it moving reference point technique. So the reference point is not always zero. And I don't use logarithmic, I'm changing this and I'm plotting my exponent versus time. So here, this area here, the green is saying I have fracture propagation, and the red is saying I have a send out. So this is telling me that fracture was propagating okay here there was some issues after about seven, about seven, eight minutes in fracture propagation. Actually, I don't have as much propagation as I thought I have. And then it went back into normal propagation, did the same thing. Then I have normal propagation here, not opening natural fracture or anything. I have normal propagation. And then at this point I started seeing movement towards sand out, and here I know we are in trouble. So, many times in, in frac pack, you don't stop as soon as you see evidence of"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "seeing movement towards sand out, and here I know we are in trouble. So, many times in, in frac pack, you don't stop as soon as you see evidence of sand out. You actually, you continue to inject. The reason for that is because the formation is very high probability, you want to create very wide fracture. So, the area, the early area you call it, you're fracturing, the later area here, you are still injecting to widen the fracture or to pack that fracture. And this is the reason we call it frac pack. Frac pack is a commercial name for Halliburton. Use it because I worked for Halliburton for 30 plus years before moving to academia 10 years ago. So, but with some others will call it frack and pack. So there is various names to it. But here you are widening that fracture. So many times people continue to inject, they are aware of it, that is it in sand out mode, but you continue to inject anyway, because you don't wanna get narrow fracture, you wanna get a wide fracture, because you're"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "is it in sand out mode, but you continue to inject anyway, because you don't wanna get narrow fracture, you wanna get a wide fracture, because you're dealing with the hyper-ability formation. And this is another example, and when I saw decline in net pressure here, and I see in this area, there was, there's actually, it seems like we propagated in height or intersected natural fracture significantly before we moved into fracture propagation. And so this was very different situation from what we expected before. And we went into the packing of fracture for most of the fracture treatment. Then we applied it to shale formation. We applied it to two cases, one Marcellus shale, that's both in the United States, and one was the Shale, that's both in the United States, and one was the Eagle Ford Shale, also in the United States. Eagle Ford Shale has produced a huge amount of oil and gas. And so, and that was an interesting situation, not going to go into much details on how we did it, but"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "has produced a huge amount of oil and gas. And so, and that was an interesting situation, not going to go into much details on how we did it, but the interesting thing, it was more or less like a blind test. And we can see here, this, every time you intersect a natural fracture, it dips. So we say we have natural fractures here, here, here. So in those areas, I can see very clear natural fracture. You pass the natural fracture and then I end getting into the fracture propagation. If you propagate the fracture some distance and boom, you intersect swarms of natural fracture and you can see it right away. So that, to me, that was, if you look at it, let me see, I don't think I applied the Nolte-Smith technique to it here. For the Egelford Shale, I saw similar things. And you can see here again, I have the intersection of natural fracture after some time, most of my fluid is leaking into natural fractures, so after, this is 190 minutes, you know that you're no fracture propagation"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "after some time, most of my fluid is leaking into natural fractures, so after, this is 190 minutes, you know that you're no fracture propagation anymore, you're just leaking off, the fluid is leaking off into, into natural fractures. So I, if I'm running the job, I say, well, at this point, I need to stop the job. Let me look at, usually going back to regular fracturing treatment, what do you do? In a typical treatment, that's what you do. And the little things have been changing a little bit these days. You have a pre-pad basically to initiate the fracture. Pre-pad usually is a lighter fluid and you're initiating the fracture, and you follow with the pad, which is basically, fracturing fluid, except it does not have propent, so you wanna, you want to widen the fracture to get it ready to, to, to bring propent in. You want the problem, you want the fracture to be a little wide when you problem going in, otherwise it will sand out immediately. I've seen a case where, where, where,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e125a6-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "you want the fracture to be a little wide when you problem going in, otherwise it will sand out immediately. I've seen a case where, where, where, where using a hundred mesh sand and since there was not enough pad or pre-pad, the fracture sand it out immediately. You don't want this to happen. So, you inject the fluid, you open up the fracture, you widen the fracture, and then you end, putting propant carrying fluid. You may end with just, again, fluid without propant, in order to, to displace the treatment deeper into fracturing, you clean the whole board, and ... sometimes this works, sometimes it doesn't, this will... ... that would take a lot of time to discuss, so I'm going to limit at that. So, what's your fraction material? You a propane selection, you have fraction fluid, you have additives, and you have fluid testing. So we'll touch in each of those a little bit, but you will have the presentation, you can look at it, and if you... I have actually a lot longer presentation"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12646-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "touch in each of those a little bit, but you will have the presentation, you can look at it, and if you... I have actually a lot longer presentation that is... goes into all those aspects in more detail. And I'll probably, what I will do, I'll put the more, the longer presentation on, send you the PDF file. May not cover it here, but will give you the presentation anyway. So let us ... for Provence, Provence is important to provide the necessary conductivity to produce the formation. If you remember, I put this equation again, if you remember, I told you almost to remember this equation if you work with fracturing. You... it's important to have fairly decent fracture conductivity. So you wanna get to, to good dimensions fracture conductivity, and this dimensions fracture conductivity is Kf which is coming from the problem, the width of the fracture which is what you injected for how long and what the pressure is, formation probability and the fracture length. So you want to get the"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "the fracture which is what you injected for how long and what the pressure is, formation probability and the fracture length. So you want to get the decent, decent I'm talking about. ... Our recommendation always was 30, for, for the, for this value, but ... higher or lower, even if you have lower value it will work well. But you want to make the design, because you lose conductivity with time, for multiple reasons. So you need to have problem that will give you that upper part here, the cond... the probability times fracture with it, so that fracture conductivity. times the fracture width, so that fracture conductivity. You don't change permeability, you change the flow regime inside the reservoir. So, where do you get this information for fracture permeability? Well, you get it from, from, from testing. But you, you know that conductivity will decline with time. There is a closure stress that may crush the problem. You know, this problem will not last forever, especially if you have"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e127a4-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "will decline with time. There is a closure stress that may crush the problem. You know, this problem will not last forever, especially if you have cycling. That is very much, that's like when you, you read, when you study metals, you talk about fatigue in metal. So the cycling producing, if you produce, you increase the stress on the problem. If you shut down in production, then the pressure builds up. So you reduce the stress on the problem. So you keep going, the cycling will cause fatigue to reduce conductivity or permeability of that problem. Embedment, part of the, the problem to get embedded into the formation, they are not infinitely stiff, so there is some embedment inside from the problem into the formation, well that obviously will reduce the fracture width and reduces fracture permeability. ... If you don't have the right fluid and the right breaker in the fluid, then there can be gel residues that plugs the, the fracture. Hopefully you work with your service company, or"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12830-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "and the right breaker in the fluid, then there can be gel residues that plugs the, the fracture. Hopefully you work with your service company, or you avoid problems like that. So this usually not, not an issue. If an issue, then somebody did not do his homework. The fine movement, it can plug a fracture. When people have developed fluid, this is a big, another subject fluids, where you, you, it, it seems counterintuitive, but you, people have added the fluids to propant, is like, it's almost like paint over the, over the propant, so covering a resin coated sand, where it, where it hold the fines, rather than let the fines, the fines move through the fraction. The ... you, you would think it's better for, for the fines to move, the, the only problem when they start moving, they get, they get, they get held near the mouth of the fracture, that's near the wall bore. And that's a disastrous thing to, to happen. ... Another issue is Digenesis. Basically degradation if you ... this is"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e128da-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "that's near the wall bore. And that's a disastrous thing to, to happen. ... Another issue is Digenesis. Basically degradation if you ... this is physical and the chemical degradation. It's ... people that work in welding, they know that when you have two different metals side by welded to one another, you could have problems there. It's like, if you don't treat your battery properly, you end having a lot of junk built on it. With diagenesis is something similar, there is electric current in the form... in all formations, this is the reason you do electric logging. And, and it ... we... experiments have been run and you leave... the experiments have been run and you leave ... leave ... propent in a fracture and water, depending on, on the composition you have there, and you can come back a month later or two months later, it doesn't look like a fracture altogether. There was a very interesting presentations on the subject that I'm not going to get into it. But, but the Digenesis is"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e1297a-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "like a fracture altogether. There was a very interesting presentations on the subject that I'm not going to get into it. But, but the Digenesis is very much what ... when you have a limestone ... ... suffering from, from Digenesis and losing it's all permeability. This is the same becoming Dolomite. So that is ... that's a Digenesis issue. So it is, it's a, it is a real issue. So there is, all of that can lead into conductivity degradation most time. So, you look, you will see graphs like this in ... in industry, you get it from... those are published, there is bunch of labs that have done those experiment. You can see, you can see plotting conductivity in millidarcy fluid versus closure stress, and it depends on the problem to concentration, the higher problem to concentration, the, the higher the fracture conductivity. But, as the closure stress increases, the conductivity declines. So, this is function in this, if I using, if I'm using one type of problem. But, also it depends on"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12a24-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "stress increases, the conductivity declines. So, this is function in this, if I using, if I'm using one type of problem. But, also it depends on the size of, of that problem. So, so there is multiple, multiple cases. So the first case we talked about, about the concentration, here I'm talking about the size, here is 12x20 mesh, that is the biggest one, ... this is the... 2040 is the one, most sandstone formation 2040 is, probably the one that's most commonly used. ... Sometimes if the formation is fairly high probability, you may fill in with, with bigger problem. To keep, to make sure that the fraction is open at the mouth of the fraction, you know what. It also depends on the type of problem. ... We hear when I use Ottawa sand, and when you talk about sand, just when I attract your attention, it's not sand you find on the beach, or find in the Sahara. Those are, are sands that are mined. So they have not been exposed to, to atmosphere for millions of years. So they are all sand"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12ac4-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "find in the Sahara. Those are, are sands that are mined. So they have not been exposed to, to atmosphere for millions of years. So they are all sand that's exposed to atmosphere for many millions of years, they are cracked and they are very weak. So they... and they are not spherical, So they, they have a bunch of issues. So when you get talk about sand, natural sand is being used, is usually, it's always actually, not just usually, it's always mine the sand. You, you mine them from underground, and then you see if they spread them into different sizes and so on and so forth. But there is also man-made material, Bauxite for example. Bauxite is Aluminum Oxide, you, you can have, it's a lot stronger. So if you have very deep well, if you have shallow well, you may use natural sand, it's cheaper to use. As the formation gets deeper and deeper, then you need to use stronger and stronger propent, otherwise it will... otherwise it will crush. There is some formation in the Gulf of Mexico,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12b64-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "then you need to use stronger and stronger propent, otherwise it will... otherwise it will crush. There is some formation in the Gulf of Mexico, that is... of Mexico that is, that almost 6 miles deep, was a poor pressure of 20 plus thousand PSI. So that's extremely high. So you have to, to fracture it and those are, I've been, I was involved in some, when we designed some fractions for them, were ... uses a very special prop and, and require a special procedures to, to work with. So, as the formation gets deeper, higher pressure, you wanna use ... better, stronger problem, maybe bigger problem. better, stronger problem, maybe bigger problem. So, this kind of schematic telling you what kind of, depending on the closure stress, what kind of problem you would use. So, very much a summary of what I said, is lower stress, you may wanna use sand, as the stress gets higher and higher, you wanna use a stronger and stronger Proven. There is actually Proven right now, I'm not going to mention"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12c04-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "as the stress gets higher and higher, you wanna use a stronger and stronger Proven. There is actually Proven right now, I'm not going to mention the name, it's commercial products, but they try to produce Proven that is more spherical and one size, so instead of saying 20, 40, it says only 40, so it is uniform size. The uniform size will give you a higher conductivity and also give you a higher strength. There is a very, very good paper, interesting paper by this gentleman, Terry Palash, SPE number is given here, interesting paper by this gentleman, Terry Pellish, SBE number is given here. I asked him to provide me some slides. So he sent me all the slides. I'm just going to use a few of his slides there. I, if you want to get more into profit, I suggest that you read his paper. Really, really excellent paper. ... He's talk about the crushing test, because in order to get this conductivity, you need to run a special test. So, he ran, he went through all those testing, he was for"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "crushing test, because in order to get this conductivity, you need to run a special test. So, he ran, he went through all those testing, he was for Carbocer ceramic, at least he used to. And he said, usually those are the assumptions that the crush test simulate realistic condition, everything is reliable and repeatable, the weight is, does not affect ... crushing, experiments, uniform packing, and he has lies to show that, none of that is really true. So, you have to be careful in picking up. So he ran, ran experiments ... and found out that, first that's the procedure they do, they, it is the equipment they, they used. ... And it said we'll, we'll, we'll ... work with it before and after. They found out it's, are the results repeatable? Not really, you can see in cases here, is a big difference in the results repeatable? Not really, you can see in cases here, there's a big difference in the results. Some are good, some are good, the difference is very small, but there is some that"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e12d44-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "can see in cases here, there's a big difference in the results. Some are good, some are good, the difference is very small, but there is some that are, from one test to another, here you see test one, two, and three, from one, two, and three, there is a, is a big difference, it can be up to 50% change, so. So, sometimes you have to take this with a grain of salt. I think pinch out can, can be an issue, pinch out can be an issue. Provence pillars, although sometimes we're going to see we people may design for Provence pillars. So you don't really have as uniform packing arrangement inside the fracture as we think we do. This one reason when you analyze data, it may not behave or did not give you exactly the results you think you achieved. There is other designs. Now many people instead of at least a few years ago or started looking at, hey, instead of, instead of trying to get uniform packing in the fraction, maybe doing something a little different. One of them like partial monolayer."}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "instead of, instead of trying to get uniform packing in the fraction, maybe doing something a little different. One of them like partial monolayer. Partial monolayer meaning that I have sand and in between, one layer of sand in between, there is nothing, nothing at all. It's just the fracture is open. If you remember the equation that I showed you last week and the fluid flow part, I'm showing you equation of fracture that is open. The permeability of an open crack is basically infinite. It's extremely high permeability. open crack is basically infinite, is extremely high permeability. So that's the idea behind partial monolayer, saying that if I have a propant that is keeping areas in between extremely high, so the average is going to be very high permeability. Well, yes, that is true, but this works only when you, when you have, when you don't have very high stress. ... Because, if the distance is very large, the fracture will pinch out in between. You, you end up having no, no"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "you don't have very high stress. ... Because, if the distance is very large, the fracture will pinch out in between. You, you end up having no, no conductivity whatsoever, no permeability. So there is, so the, you, you apply those techniques with, with, you know, it's, it's not just one solution fits all. ... Pillar frack and the highway frack, they are, and conductor frack, they are all the same thing, and that is ... this, with, with names given by different, ... different service companies. And basically saying, a pillar frac is a very old idea, is similar to partial monolayer, except you say, well I do have multiple, multiple layers inside the fracture and in between, so I have a pillar and pillars and between the pillars I have basically empty area, so open fracture, so the average is, is very high probability. And it actually, you know, I've seen results in more than one country, in one place, and you can't argue with success. They do work well. The production was a lot higher,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "know, I've seen results in more than one country, in one place, and you can't argue with success. They do work well. The production was a lot higher, at least initial production. The one thing one has to worry about is to look at the long-term production. So make sure that you don't have sharp degradation or closure pinch out inside the fracture. This is one case that I have seen. This company run this case in Eagle Ford and said, hey, they did it using one of those fractures, I think it was a conductor frack, and it saved the 1 million pounds of profit. But the one thing one has to remember here is also this is an Eagle Ford. And so the production from natural fracture is very important, and the formation has, itself has very low probability. So you do not need really a huge amount of, of problems. When this was the conductor frack, where you have 30 second burst, so your, your system is, the injection is set to half burst every 30 seconds of problem. It ... it did, at least the"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "where you have 30 second burst, so your, your system is, the injection is set to half burst every 30 seconds of problem. It ... it did, at least the claim that it did work, it produced at least as much fluid when saving is one million pounds of sand. Fraction fluids, you wanna get it, your... fraction fluids will give you viscosity that controls weight, that impact the transport. You have control fluid loss, so you... you... you build a filter cake, very much like the mud cake that you... you see in drilling. In drilling you... you wanna build the mud cake to prevent drilling fluid to leak into the formation. Here you do similar thing, you filter cake, so it is a similar concept. So you lose a little bit of fluid and it builds a filter cake, so you, it prevents further loss. ... It has, it provides some density, and it gives you a hydrostatic head. And also it helps in, in settling of the fluid, both the viscosity and the density will help in ... in settling, control settling of"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "head. And also it helps in, in settling of the fluid, both the viscosity and the density will help in ... in settling, control settling of Profit. ... Friction pressure, it, you wanna reduce friction pressure, otherwise this is, this would be horsepower that you would ... one would be losing. And, you wanna control cross linkers, you wanna make sure you don't damage the formation, this will get into... into it in a minute. Fluids, when you look at fluids, I'm sure that you, all of you, know about that. I have Newtonian fluid, basically if I plot shear stress versus shear rate, if I have Newtonian fluid like water, then it's a straight line, basically at zero shear stress, I have zero shear rate, there is no movement, and it is, follows linear behavior like this. The slope of this line is your viscosity of the fluid. Okay? In... in all industry, in fracturing, you are not using Newtonian fluid, you are using non-Newtonian fluid. Non-Newtonian fluids, it can be different types. One is"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e13226-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "in fracturing, you are not using Newtonian fluid, you are using non-Newtonian fluid. Non-Newtonian fluids, it can be different types. One is Bingham plastic, which it takes yield stress. So, there has to be some stress before the fluid can move. And this is important to make sure that, that ... cuttings do not drop to the bottom of the well, when you stop circulating, otherwise it becomes a huge issue. And then from there, it can either follow up, the fluid follows a straight line, it'll be like Newtonian fluid, or it could be actually even a curve. For the non-Newtonian fluid that we use in fracturing is the pseudo-plastic, so it is, it's a curve like this, where we say, shear stress is equal to some constant, times shear rate, raised to some power. We'll write the equation in a minute. So it is a, is a equation of a curve where that power which you're in the prime is less than one. So let me show you the, the equation, here, this is the power law, power law equation. It's this"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "power which you're in the prime is less than one. So let me show you the, the equation, here, this is the power law, power law equation. It's this constant, K' times, Shear rate, times to the power of N' and N' is less than one, so, so here, so what is the viscosity of this fluid? Well actually, there is no viscosity, there is an apparent viscosity. So, you, you can see, as it gets, I'm going to talk, I'll show you a question for apparent viscosity, but the apparent viscosity here, is basically, if I wanna get the apparent viscosity at this point, I draw a straight line down to zero. So you can see that the straight line gets flatter, and the flatter as the shear rate gets higher. So that is shear thinning fluid. So it acts as a, thinning fluid. So it acts as a, as a lower viscosity fluid as the shear rate gets faster. So that's what you use in fracturing fluid. And this is opposite to dilatant, that you do not use dilatant in fracturing fluid. And dilatant is the exponent, the"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "you use in fracturing fluid. And this is opposite to dilatant, that you do not use dilatant in fracturing fluid. And dilatant is the exponent, the exponent is larger than one. And so you can see that the shear rate, as the shear rate gets larger, the apparent viscosity gets higher. And so here is what I, basically this is the equation for the model and apparent viscosity here, you can see for fracturing fluid, the apparent viscosity is the slope of this line. So as the shear rate gets larger, the fluid behaves as if it is thinner. So it's a shear thinning fluid. And the equation for apparent viscosity looks like this. Many people think it is the tangent. So please make sure you understand that it is the line going from zero to that point. And so, if I have a linear gel, water, the N prime is one. This is the K prime is 1, this is the K prime, is that value, the viscosity as you put it in, in, in this little, you apply the shear rate to it, at shear rate of 170 inverse of a second,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e13424-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "K prime, is that value, the viscosity as you put it in, in, in this little, you apply the shear rate to it, at shear rate of 170 inverse of a second, you, water is 1, basically the viscosity is constant, it's 1. Linear gel, linear gel is, NA prime is 0.8, if you have cross-linked gel, we're not going to get very much into that, the NA prime can be as low as 0.5. So, the requirement, I'm... we're running out of time, so I will just show you those... It has a lot of requirements, one of them is to maintain... it has to be cost effective of course, but you wanna maintain viscosity. You wanna maintain viscosity, you to have the fluid to keep the propant being held in place, until you try to close that fracture. And you want to be able to, to adjust this viscosity. You see this is, I will let you read this requirement. ... There is water based, like what we discussed before, most of the fraction fluid now is water based. At one time people used a lot of energized fluid, ... Nitrogen, CO2"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e134c4-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "like what we discussed before, most of the fraction fluid now is water based. At one time people used a lot of energized fluid, ... Nitrogen, CO2 or a mix of the two. This is the foam based fluid, it's not used as much, in the presentation I'm going to send you, I was going to tell you why, essentially although foam is very good in carrying propant and transporting prop, foam does not have much Hydroceticate, so... So, it has a special application. Oil based fluid, is ... it's still being used, but is not as... as popular, because of ... potential risk factor. ... The people have used the Acid, we use the Acid a lot in ... in fracturing Carbonate fluids. ... Oh yeah. Not going to get much in, so linear gel, there is different kinds. This I will, I will leave it up to you to, much in. So, linear gel, there is different kinds. This I will, I will leave it up to you to, to read, especially chemical names like this is, is not that easy to pronounce. But, we have used Acid, Acid Frags and"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e1355a-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "I will leave it up to you to, to read, especially chemical names like this is, is not that easy to pronounce. But, we have used Acid, Acid Frags and Acidizing in general. We actually spend, acidizing in general. We actually spend ... in, in the regular class, we spend some time on, on acidizing. Because it can be very important, especially in Carbonate formation. There is even Acid has been used for sandstone, you could acidize sandstone formation. However, when you acidize sandstone formation, is essentially to remove damage. For Carbonate formation is to, is to create wormholes or improve average permeability around, around the workbore. ... Cross-linked fluid ... you, you wanna use it when, when you have high problem concentration. If you're fracturing shale, you probably do not need to do that, because you do not need to, to use much, much problem to concentration at all. And, cross-linked fluid can be different types with. Some of these heavy metals are being frowned upon right"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "much problem to concentration at all. And, cross-linked fluid can be different types with. Some of these heavy metals are being frowned upon right now. People don't want to use ... Titanium, Zirconium or, or even Aluminum. ... You, now there's a lot of move towards using organic crosslinkers. We, I know we, we got involved very much into using organic crosslinkers for, for, for conformance fluid, and same thing applies to, to fraction fluids. ... So, the crosslinkers depending on, on what you use, ... Titanium of course is, it is permanent, it's shear sensitive, it, it can be variable. There is, there's a lot of decline in using things like that. ... Because, they, they are cross, they are cancer causing agents, and many, many places actually prevents you from, or prevents service companies from using heavy metals and, and fluids. Energized fluids, we talked about it already a little bit. Energized fluids, we talked about it already a little bit. It's... it was more popular in... in"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "fluids, we talked about it already a little bit. Energized fluids, we talked about it already a little bit. It's... it was more popular in... in 80's and late 80's, basically for... for reasons for carrying propent and if it's not very deep formation. There is very low leak off, so it is ... it works very well in this situation. And so, and so here basically is loss control, is carrying ability, but ... the biggest disadvantage is lower hydrostatic head, and it may have very high friction pressure. In models, we'll, now I have, people, we used to use, we used the 2D model years ago, people now do not use 2D, we use 3D and the full 3D models. You can look at it, 2D models is, people have stopped using it for a very long time. It's basically because of computers now are a lot more sophisticated, you can run models very fast, both the pseudo 3D and the full 3D models. The full 3D models have the advantage of looking at layering system in a more complete way. So that's actually what you"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e1374e-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "3D and the full 3D models. The full 3D models have the advantage of looking at layering system in a more complete way. So that's actually what you want to use is the fully 3D model. It gives you maybe a better picture of what is going on. So the 3D model, although it may look at the stresses, but does not look at the layering system and what is going on really accurately. And very similar to the fluid flow models. You wanna have fluid flow models, you want to look at 3D model, looking at what is going on, the effect of each layer accurately, rather than, rather than approximating that behavior. So lately we, everybody has been working on the fully 3D model. Starting the mid 90s, the use of 3D model has mushroomed. Even at University of Houston, we're developing models, where we develop the full 3D model. Because when I look at stresses more accurately, when I look at layers more accurately, you wanna see these effects and design your fractional treatment. ... So, a 2D models is not"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e13866-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "more accurately, when I look at layers more accurately, you wanna see these effects and design your fractional treatment. ... So, a 2D models is not being used, I need to remove it from here. Pseudo-3D model, there's two different types, some are really used cell model, but the ones that you really wanna be using, is, is fully 3D model model to calculate height, width and length correctly. A pseudo 3D model there's a lot of assumptions where you really don't, don't calculate the tree, although they pretend to be calculating all those models but, but it's with a, with a great deal of assumptions. So that takes care of the presentation. I'm going to put in, I put it in Researchgate and I'll send the link to Dr. Elgarhi where you can download this presentation. What I'm going to put on is going to be a little bit more expanded presentation. Thank you, Dr. Solomon for a very informative webinar. I'm sure the audience has benefited greatly from it. In the meantime, I've collected a few"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: d6e13924-8641-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "Thank you, Dr. Solomon for a very informative webinar. I'm sure the audience has benefited greatly from it. In the meantime, I've collected a few questions for a quick Q&A session. What are the reservoir quick Q&A session. What are the reservoir parameters we can get from the square root of time technique and the g function? Okay, I'm going to cover the g function next week. So I, g function does not give you reservoir properties. It actually gives you leak off coefficient. There have been techniques that were developed to analyze the data, the same data to get formation probability. I will go through those techniques. We have, we developed our own techniques as well as those techniques and, and literature will cover all of those next week. So maybe we need to wait for next week to talk about. G-function is very important and we'll cover it. There's some advantage, disadvantage of using G-Function, but we'll discuss it next week. So that will be an incentive for you to attend the next"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "it. There's some advantage, disadvantage of using G-Function, but we'll discuss it next week. So that will be an incentive for you to attend the next week. The second question is, how can we solve an issue of propane flow back near wellbore? That's a very good question. And I have seen this issue many, many times. We actually working on, we have a PhD dissertation, the student that's working on an issue like that. We have, there was always suggestion that you tail end with maybe resin coated sand. One thing is not to follow the treatment with water thing is not to follow the treatment with water or with non-carrying fluid. So when you have problems moving into the whirlpool, you're being replaced by problem to deeper. but having resin coated sand or some treated propent is, is probably the best, the best idea. ... You could allow for fluid to leak off for short time before you, you start flowing back, because the... just I need to mention, you, you wanna do some flow back to close the"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "to leak off for short time before you, you start flowing back, because the... just I need to mention, you, you wanna do some flow back to close the fracture, because you don't wanna wait for forever. So, if you have resin coated propent, that may or similar, there is multiple, multiple types of fluid, there's some use fibers for example, that's another commercial techniques to show you. That, that will allow the problem to be sticky near the, if you, if you follow a futility with, with this type of problem, it becomes a sticky near the wheel bore, so it prevents it, allows only fluid to move in without having the problem moving back. But that's always an ... a big issue. ... Another question is, which size of propent is commonly used with shale fracturing? They ... most of the propent I've seen was essentially sand. ... You know, I know that various types of sand, like Brady sand, well which is not being used anymore, but ... So, you do not need huge conductivity in shale. ... The"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "that various types of sand, like Brady sand, well which is not being used anymore, but ... So, you do not need huge conductivity in shale. ... The reason for that is for, if you look at that equation, formation permeability is very, very small. And so you, you do not need very high fracture conductivity. Sometimes your people would tell you that the mere fact that you open up the fracture, the... the... just... just the... the grains from the formation will give that fracture high enough conductivity. I always recommended that you use some prop... So people... I think, I believe sand is ... is the most common ... proper to use in there. But that's a good question, I will, I will... Things keep changing, I will double check on it and I will let you know next time. But I... the cases I've been involved in was mostly sand. For... I'm talking about for shale. Another question, Dr. Solomon, you mentioned KIC and HS. What is the relation between them? Between KIC and what? HS. HS? Yes. What"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "about for shale. Another question, Dr. Solomon, you mentioned KIC and HS. What is the relation between them? Between KIC and what? HS. HS? Yes. What is SHS? H S? Yes. What... What is S H S? I'm not sure the question is... Maybe he means a horizontal stresses for example? I ... I don't know what he, this, when he stress you say sigma. We talked about later on and. Dr. Solomon, you know, because he is writing and he cannot have the Greek. Oh, I saw. Maybe he mean horizontal. No, no, no, no, no. Okay, this one. Yeah, I, now I, it's talk about height. Okay, this is formation thickness. H is formation thickness. HS is the penetration of the fractures into the upper and lower zone. So, if I have symmetric case, I'm calling this HS. This is ... actually I ended the calling it A and B in the next equation. This KIC is a property of the rock, not of the fracture. It's a property of the rock. When we look at it in sandstone, we say KIC is 1200 to 1500 P size per root of inch. That's property of"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "of the fracture. It's a property of the rock. When we look at it in sandstone, we say KIC is 1200 to 1500 P size per root of inch. That's property of the rock. That is the value that the fracture has to overcome and in order for it to propagate. So in this case, the stress intensity factor, not the critical factor, it will be the pressure inside the fracture, P times this whole thing, which will be H over two plus HS. Okay? So if this value, the pressure times that height is higher than KIC, the fracture will continue to propagate in height. So it is the height of the fracture at very early on before it propagates into the upper and lower zone. If the fracture is so small here, then you're talking about, you're talking about the pressure times that height. Okay. Did I answer your question? So. I think you did Dr. Solomon. Yeah, this concludes our Q&A session. There's another question about G, about the square root of time and g-function, but we'll save that for next webinar. Yeah,"}


created_at: 2023-11-18 18:45:36
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 03-04.txt", "chroma:document": "our Q&A session. There's another question about G, about the square root of time and g-function, but we'll save that for next webinar. Yeah, we'll cover the analysis next time. I may expand it. Testing, you know, it can take a lot of time. We'll cover some of it and then we'll see. Yeah, so yeah, thank you Dr. Salomon for deciding some of the time of your surely busy schedule to give this webinar. We are all grateful. Thank you attendees for tuning in from all over the world. Stay safe, wear a mask and have a great day. Thank you very much. Stay safe, wear a mask, and have a great day. Thank you very much."}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "So good morning, good afternoon and good evening. Hope you are all doing well and staying safe. I am Maryam Shref, a senior petroleum engineering student at the Lebanese American University, and I'll be moderating today's session. So it's my pleasure on the behalf of Payo Petro to welcome you all to the fourth and last lecture of the online course, Hydraulic Fracturing, which has been presented by a special distinguished speaker, Dr Mohammed Solomon. I'm sure that his participation with us has benefited all attendees and added a lot to their knowledge. So let me begin by reintroducing Professor Solomon. So Professor Solomon is the chairman of the Petroleum Engineering Department at University of Houston. Dr. Solomon has a long industrial and academic experience. He holds 35 patents on fracturing operations and analysis, testing and conformance applications. He is the author and co-author of over 250 technical papers and articles in various areas of petroleum engineeringventors. He is"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "applications. He is the author and co-author of over 250 technical papers and articles in various areas of petroleum engineeringventors. He is a professor of political papers and articles in various areas of petroleum engineering. Dr Solomon is a registered professional engineer in the state of Texas. He is also a distinguished member of the Society of Petroleum Engineers and fellow of the National Academy of the Inventors. To highlight he authored several books book chapters on stimulation and testing. Additionally, he's the primary editor of Fracturing Horizontal Wells, published by McCrowhill in 2016. He's the author of Optimization of Hydraulic Fracture Stages and Sequences in Unconventional Formations, published in 2018 by CRC. Finally, Dr. Solomon holds a Bachelor of Science with top honors from Cairo University and the PhD degree from the University of California, California, PRC. Finally Dr Solomon holds a bachelor of science with top honors from Carter University and masters"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "from the University of California, California, PRC. Finally Dr Solomon holds a bachelor of science with top honors from Carter University and masters and a PhD degree from Stanford University, all in petroleum engineering. So please join me in welcoming Dr Solomon. So, Doctor, we are pleasured to have you with us today and thank you for the time you have dedicated to deliver this course and for supporting a bio Petra's vision and mission, which is mainly focused on maximizing oil and gas digital content and raising educational standards by providing students, professionals and members with a large library of digital resources. And on a final note before proceeding with the session, if you have any questions related to the technical content of the presentation, please feel free to drop it down in the Q&A section, and we will try to answer as many questions as possible. And as a reminder, don't forget to solve the last quiz for this course and do the final exam, which will be held on"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "as many questions as possible. And as a reminder, don't forget to solve the last quiz for this course and do the final exam, which will be held on Tuesday, the 3rd of November, at 2pm and 8pm Egypt time, and also 2am Egypt time Wednesday. However, you are only allowed to attend and submit one exam, depending on the time and date that suits you the most. Without any delay, Dr. Salaman, the mic is yours. Thank you very much for the introduction. Good morning everyone or good evening, depending on where you are. It is 10 in the morning here in Houston. This is the last lecture we're going to discuss on fracturing testing. Please remember this is an introduction to fracturing, it's a very basic school. Testing or any of the subjects we have discussed so far would take many hours to go in in details on them and that is definitely for in details on them. And that is definitely for testing too. I will introduce you to testing, which is specialized to fracturing. Parts of it, in order to go"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "on them. And that is definitely for testing too. I will introduce you to testing, which is specialized to fracturing. Parts of it, in order to go into all details, one has to have, a student has to have a background in wood testing because some is built on wood testing as well as on fracturing issues. So let us, let us start talking about it, let me see. Why tests are runs? Well, tests are runs like in what we see in well testing. We want to understand the formation, however tests and fracturing, they are run to get not just the physical properties but mechanical properties as well. If you are familiar with this thing, you run it, you say I want to get formation probability and skin factor. Here you may want to get also mechanical properties or stress field. When we discussed ... fracturing in the last three lectures, we talked about the importance of mechanical properties, we also talked about the stress field, the magnitude of stress, as well as the orientation of stress. So, some"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "importance of mechanical properties, we also talked about the stress field, the magnitude of stress, as well as the orientation of stress. So, some of those tests are designed to get those properties, because they affect the fracturing very much. So it goes beyond the, just the physical properties. So there are techniques where you calculate formation probability, or initially you calculate a leak off coefficient, you wanna calculate fraction length, fraction efficiency, we'll talk about all of that. There are newer techniques that have been developed and being developed, not just ... So, we'll mention some of those techniques, we are not going to discuss them in details, there was a lot of research including including here at the, at University of Houston, I have several students working on different areas that you find very interesting, including a paper that we, one of my students just presented yesterday in the annual technical conference. And once you get all this information,"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "including a paper that we, one of my students just presented yesterday in the annual technical conference. And once you get all this information, you're going to predict the formation response, response during the fracturing process, you're going to predict the production, what happens, you're going to optimize, you're going to get the best fracturing treatment, and optimum fracturing treatment. The type of tests, we are going to talk about several types. Some of them, I'm going to call them pump and flow back tests, we'll talk about the step rate test, step up as well as the step down tests. They are a little different, it's not exactly the same thing as we are going to see in a minute. And we are going to talk about pump and shutting tests. You call it DFIT, you call it Manifrac, depending on. DFIT is the name that's used mostly now, although you are going to find the name Manifrac used a lot at one time. People called it also DataFrac, Data data test, FAT, but most of the time now"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "you are going to find the name Manifrac used a lot at one time. People called it also DataFrac, Data data test, FAT, but most of the time now people refer to it as DFIT or mini-frag. Then you have leak of test and extended leak of test, that's during drilling and when you think about it, it is really not very different from what we have in DFIT except it's during drilling. We analyze the sum of this data very much like what we, the way we analyze DFIT. So it may be only name and the, the, when you run the test. So let us talk about, first about pump and flow back test. And that is type of test which we used to, we have run many, many years ago, but maybe in late eighties, early nineties, was very popular. We called it a micro frac. And as you are going to see in a minute after we discuss it, it actually is making a comeback and many companies are rerunning this test but not exactly the same way we used to do it in a little different fashion, I would say. In this specific test, it was,"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "are rerunning this test but not exactly the same way we used to do it in a little different fashion, I would say. In this specific test, it was, the idea was to create a small fracture, fairly small fracture, and ... the, the reason you wanna create small fracture with smaller ... injection volume is, is to make sure that the stresses inside the formation don't change very much. So that is the reason behind it. And we're looking, we're going to look at the test in a second. Once you, you fracture the formation, and you are doing it during drilling. So I go into the area where I, even above the pay zone, above the pay zone, in the pay zone, below the pay zone, above the pay zone, in the pay zone, below the pay zone, create fractures there, and ... if I analyze the data, the pumping and the flow back, I'll be able to get when the fracture closes, and I say, hey, when the fracture closes, this is my minimum in-situ stress. The reason is very close to minimum in-situ stress is because the"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "and I say, hey, when the fracture closes, this is my minimum in-situ stress. The reason is very close to minimum in-situ stress is because the injected volume is very small. Once I do that, I recover an oriented core. And that oriented core can tell me a fracture orientation. We'll look at the examples in a minute. So I can determine closure pressure, which would be essentially the minimum situ stress. I will recover a fracture and that will give me the orientation. So I, from there I determine the stress field, the magnitude and so. So, so what, what we, we, the idea behind this test is to come down to the area where I want to test, and this is during drilling, and this can be, as I said, above the pay zone, in the pay zone, below the pay zone. Actually, the recommendation was to do it in the three areas, to get stresses in the pay zone, as well as in surrounding zones. Like what we discussed last time, to see whether fracture would propagate upward or downward. So I put the drill"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "as well as in surrounding zones. Like what we discussed last time, to see whether fracture would propagate upward or downward. So I put the drill pipe and I replace the drilling bit with the perforated anchor, like what I see here, I put an inflatable packer, and we go down, we isolate... we... we isolate this area at... at the bottom here, or the bottom of the well. I received the packer, inflate the packer, so receive this area, so it will be isolated. I inject inside the drill pipe. I fracture this formation, and the fracture as you can see, is going to go sideways, it going to go upward also, and monitoring pressure both below, below the packer, as well as inside the drill pipe and in the annulus. Once ... I can tell right away whether, whether the, the fracture whether the fracture got around the inflatable packer or not by monitoring the pressure. So usually what we did, if I see a higher pressure in the analysts, I would stop the test, because obviously the fracture went above"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "the pressure. So usually what we did, if I see a higher pressure in the analysts, I would stop the test, because obviously the fracture went above the package. So we could, once you've done the test, I pull out the drill pipe, I go back with a coring tool and I core an oriented core. Oriented core, basically I'm going to see one in a second. It is a core where it is etched on the side, and the service company would tell you, the coring company will tell you which orientation that line is, it's like a scribe mark on the core. So, if I know it is, it, it tells me this line here is in, in say, 20 degrees East of North, ... and the fracture is going 70 degrees ... to it, then I know exactly the orientation of the fracture in space. So, that is the, the whole idea. ... This, I showed you this test before, that was actually a micro-frag that was run, you can see the breakdown pressure, we shut down, then we inject it again, we reopen pressure like what we discussed before. And I find that"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "was run, you can see the breakdown pressure, we shut down, then we inject it again, we reopen pressure like what we discussed before. And I find that fracture closure pressure that I find here, and we'll look at more detailed tests in a second, that since I injected very small amount of fluid and you'll be surprised, we used to inject just a couple of barrels over a few minutes. Since the volume that was injected was very small, the fracture, the stresses inside the formation have not changed. So my closure pressure would be very, very close to my minimum in-situ stress. So as, as the injection pressures, injection volume gets a higher and the higher that fluid will leak off and the value that I see in closure pressure may become different from minimum in-situ stress. So let's just look at an actual case that this part of a paper that we published some time ago myself and Dr. Ali Danesheh in SPE21400. This is some time ago when we ran this microfrag and you can see we're injecting"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "we published some time ago myself and Dr. Ali Danesheh in SPE21400. This is some time ago when we ran this microfrag and you can see we're injecting here at about eight gallons per minute. It lasted about 15 minutes or so from 10 to seven, to seven, five to seven to 10 minutes after seven. So for 15 minutes, eight gallons, that's 120 gallons, that's a little less than three barrels of liquid. So you inject and right away, we will flow back. And I'm flowing back here at about three gallons per minute. This actually required developing or building a special tool to be able to control that constant injection rate. It's a lot easier in situations like this to inject at a constant rate than flow back at a constant rate. So always flow back at constant rate is fairly difficult. And we want it to flow back at a rate that will give us the pressure drop. You see here, I'm fracturing and fracture propagating for only 15 minutes, I'm shutting down and I want to get an inflection. At least this"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "drop. You see here, I'm fracturing and fracture propagating for only 15 minutes, I'm shutting down and I want to get an inflection. At least this was the idea we had at the time, that if we see the inflection, and people used to argue, what the closure pressure? If you read that paper, we did complete analysis, not only on this test, this was one example, but in multiple tests like this, and we figured out, at least we were at the time, and now we believe that this would be, the area here would be the full closure at a little less than 6,400, that dashed line. So that would give us the closure pressure and minimum situ stress. Look at this, some of the cores that we recovered. I hope you can see this line here. You see, you can see the fracture where it broke, where the recovered this fractured core. But above the fracture at an angle to it, there is a scribe mark. And this is like etching in... in the core. That is your... that is where I said, the coring company will come and tell"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "it, there is a scribe mark. And this is like etching in... in the core. That is your... that is where I said, the coring company will come and tell you that, Hey you, your fracture or your... your core was oriented at such and such ... degree. So you... this was a vertical well, is not a deviated well. And so I look at it, I know the orientation of... of the core, I know what angle is the... the fracture is located with respect to the core, then I... I know exactly orientation of, of the stress. Because I know that the fracture is perpendicular to minimum stress, I know the orientation of the fracture, I know the stresses, I know the orientation of stress, and the test also give me the magnitude of stress, so having these two together works very well. So, that defines the stress field. This is another example, the long example, where we recover the longer core. This was also interesting because, if you look at the corner here, and you can see this is the end of the fracture. So it ..."}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "the longer core. This was also interesting because, if you look at the corner here, and you can see this is the end of the fracture. So it ... it shows how the fracture ended. Actually it went to an angle to, to the core. And that is ... several feet of ... of core. It's probably about 5, 6 feet or so. And that we brought to, this we brought it to our lab. This is something that we did myself, and we're taking those pictures. Can you run it on wire line tools? Absolutely. Actually, even at the time we, those ideas of running on wire line tools and many companies right now, they have come up with better equipment to be able to run that micro frack after you drill the well. So you can run it on the various tools. I know that Slumber J built a more advanced MDT that is still selling very well. But other companies, I'm sure they are doing the same thing. RDT, I think with Halliburton, CRD with Baker Hughes at the time, whether they maintain them or not, I know MDT and RDT is still used"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "the same thing. RDT, I think with Halliburton, CRD with Baker Hughes at the time, whether they maintain them or not, I know MDT and RDT is still used very much and they are running them in microfrag. ... Some people, it's almost funny, but they did not realize that we have been running microfrag on drill pipe, many, for a very long time, and we did it first as research, then as a, as a service. ... However, the way we, when we ran it on drill pipe, we extracted core, you know, we recovered an oriented core. Of course, after you drill the well, there is no more core zone, you're running a wireline tool, formation tester. So, no core is extracted. So, you can determine formation, you, you will be able to say something about stresses, you could even before that, you can run a well test and determine formation permeability. The step rate test, step up, sorry for this, not sure what it is, but for a step up, step up rate, basically you are stepping up the rate from below fracturing to"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "test, step up, sorry for this, not sure what it is, but for a step up, step up rate, basically you are stepping up the rate from below fracturing to above fracturing, and the idea is to determine the fracture opening pressure. So this is a real example we have run, I was a co-author on that paper by Stanton. We went to the field and we ran bunch of tests. One of them was a step-up rate test. Basically, you're starting at low rate, you monitor the rate for ... you keep constant rate for a little bit of time, monitor pressure, then increase the rate, monitor pressure and so on. And, it, it would look something like what we have here, and then... the, the idea that before the fracture is opened, the, you, to increase rate from one value to another, it require fairly high pressure, high pressure increase. So that the interval in the stem pressure is high when the formation is not fractured. Once you fracture it, then it is easier to inject the fluid. So you go from one rate to a little"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "is high when the formation is not fractured. Once you fracture it, then it is easier to inject the fluid. So you go from one rate to a little higher rate, you don't have to increase the pressure as much as if it was not fractured. So that is the basic idea. That has been done many, many times. And it looks something like that. This is very much what I'm saying. So I plot bottom hole pressure versus injection rate. And you can see before fracturing, in order to, the gradient is high, which tells me for per unit pressure increase I need, per unit rate increase I need higher pressure. So that gives me a higher slope. Once the formation is fractured, it should be lower slope. I can increase the rate without increasing the pressure very much. So if I have data below and above fraction opening pressure, it will look something like this. I will draw two straight lines. The intersection of the straight line is my extension pressure. And so it is, this test has been done many times. It's very"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "draw two straight lines. The intersection of the straight line is my extension pressure. And so it is, this test has been done many times. It's very valuable test to do. The even better test that was developed several years ago, just for fracturing, is a step-down test. And it's a little different, for fracturing is a step-down test. And this is a little different because, let me describe it before I get into these equations. And I'm going to show you an example. It was a step-down test. I'm not going from above fracturing to below fracturing. I'm always above fracturing. So I am running a test where my rate, I'm reducing rate above fracturing pressure and trying to see what happens. Where, how much change in pressure is going to depend on the condition of the well, the perforations, if there is tortuosity in, around the well bore. If the fracture going straight, say if my perforation are oriented with my, with my, with my fracture orientation and have large number of perforations,"}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "the fracture going straight, say if my perforation are oriented with my, with my, with my fracture orientation and have large number of perforations, then I don't see a whole lot of pressure drop in perforation. If the fracture is turning around, then you see tortuosity, like what we saw in this example, we looked at before the fracture face may become very rough. So I see a high pressure drop. look bad before the fracture face may become very rough. So I see a high pressure drop. And so by looking at how pressure changing would rate, I may be able to tell the condition of the fracture as it intersects the wood board and if there is something that I need to do to take care of a problem if there is one. So I just want to remind you of this equation here. I just want to remind you of the basic equation. We look at, you know, friction and pipes is something like this. we look at, you know, friction and pipes is something like this, ... Reynolds number of, for fluid flow in, here in pipe."}


created_at: 2023-11-18 18:50:12
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "is something like this. we look at, you know, friction and pipes is something like this, ... Reynolds number of, for fluid flow in, here in pipe. So, if I have fluid flow in pipe, I, I can create a Reynolds number here, if I have, if I have laminar flow, my friction factor is, is like this. If it's turbine flow, then you need the chart to do it. And, friction inside perforation follows an equation like this, if it's turbine flow, then you need the chart to do it. Friction inside perforation follows an equation like this. I'm not going to go through all those details of the equation, but number of perforation is very important. The diameter of perforation is important. And this discharge coefficient is very important too. Discharge coefficient is very, is very important too. So you're, so I, if I don't have enough perforation, you expect this number to go up very high. So you have very high friction pressure. So the way we look at it, if I go into a step-down test, my pressure drop"}


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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "this number to go up very high. So you have very high friction pressure. So the way we look at it, if I go into a step-down test, my pressure drop should be, should look something like this above the top equation. The delta P is equal to some constant times rate raised to some power. And instead of using the equation as is, it is easier to take the logarithm of it. And I say log of delta P, equal to some constant, which is log of A, whatever A is, times that exponent B, times log of rate. So if I plot log of delta P, and you notice that now I need to know, I need to know closure pressure. So this pressure above closure. If I plot the log of delta P versus log of Q, then that is, will give me a straight line. The slope of the straight line will tell me something about the connection between the wood borer and the formation. So if the slope is very high, that usually, if you look back at the equation for perforation, that usually tells me there's not enough perforations. That usually"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90bde-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "is very high, that usually, if you look back at the equation for perforation, that usually tells me there's not enough perforations. That usually does not happen. If it happens, that means one has not designed the fracturing properly. Although we have seen cases, we've seen cases where perforations were not sufficient, that doesn't happen very often. Okay, so if this is the situation, the obvious solution is to go back and re-perforate. Otherwise you'll have a lot of issues in the fracturing treatment. So that you run the test before the fracturing treatment, then you go back and re-perforate. And most of the time, before vertical well you perforate about, the common perforation scheme is six shots per foot, 60 degree facing. If it's fractured horizontal well, then you build a cluster, lots of perforation in a cluster. We did not talk very much about fracturing horizontal wells, but this is another subject that's extremely interesting. We'll not be able much about Fraction Horizontal"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90c88-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "much about fracturing horizontal wells, but this is another subject that's extremely interesting. We'll not be able much about Fraction Horizontal Wells, but this is, this is another subject that's extremely interesting, we'll not be able to cover here, but if you look at, at that book that I, we published, it has very nice chapters, multiple chapters on, actually the whole book is about Fraction Horizontal I'm part of one couple of chapters on the right mechanics part of it. If I get a slope of 0.5 to 1, that may be maybe a tortuous path. Tortuous path meaning that the fracture is turning around, meaning that the fracture is turning around. And, many people have decided, well, if I see that in the, in the test, that tells me that the fracture is, has very rough surface, is turning around. And, what do you do if you have rough surface? You know, if you are a carpenter and you have a rough surface you use sandpaper to smooth it out and that's exactly what people have suggested to use"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90d28-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "You know, if you are a carpenter and you have a rough surface you use sandpaper to smooth it out and that's exactly what people have suggested to use and I'll show a real example with this was exactly used. So you use you inject propant or sand you use, you inject propent or sand, but on slugs, not continuous sand, but you inject the slugs as it goes in, it's essentially smoothens the surface of sand, of the fracture, and it reduces the pressure, the friction pressure. If I have a slope of, let's say of 0.25 or so, around this slope, that usually indication that things are going okay and you can just fracture. When you get into fracture horizontal welds, pressure drop is a lot higher and without any problems. It is the nature of the fracturing and fracturing horizontal words. Maybe in the future we have a lecture on it. This is an example that was published by, I forgot to put the date on it, by Hayden and Stijend. They actually ran a case, they published multiple cases, they were"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90dbe-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "that was published by, I forgot to put the date on it, by Hayden and Stijend. They actually ran a case, they published multiple cases, they were looking at testing. And they got fairly sharp slope, so they ran back almost like another test, injecting with slugs or propane, and then they run the step down test and they're very much like what people would expect. The net pressure not only dropped, so you're seeing there's a lot of friction pressure that was removed, not only that, the slope also became flatter. So, that was a very successful situation they, they handled. By the way, Hayden and Stijns are really great people in, in fracturing. I've known them for many years. I've known them for many years. Determination of closure pressure, we sometimes in tests like this, we, if you would use a square root of time graph, that was been idea is, the idea is basically following Carter's equation. So let us talk about the tests that estimation of when you want to estimate, not just the"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90e5e-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "idea is, the idea is basically following Carter's equation. So let us talk about the tests that estimation of when you want to estimate, not just the closure pressure, but you want to leak off coefficient, maybe formation probability, poor pressure, all this information. There's a lot of information that one can recover from many frac tests or DFIT. I'm going to talk about the basic stuff. Well, unfortunately we would not have the time or it takes a lot more time to go into all the details. So the original technique that was developed was developed by Nolte, it was ... at the time he was working for Amaco, later on joined Slumber J. And the paper that he wrote is SPE 8341, as I'm writing here. It's really classical paper. ... You... you... I would advise you to read it, although it is not an easy paper to read. I... I have to tell you that, but ... we're going to go through the basic technique here. We'll not go through the derivation, but through the basic technique. But it's an"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90efe-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "that, but ... we're going to go through the basic technique here. We'll not go through the derivation, but through the basic technique. But it's an excellent paper that started all those ideas of testing. Then once Nolte published his paper there was multiple papers afterwards on modification of this technique, updating the technique that is used as g-function derivative analysis. Nolte is the one that came up with g-function but it's not exactly the way people use it right now. We're going to go through both. And so let us talk first about Noltes technique and that will give you an understanding of what he did and then we go further into it. So the original technique was depending on type curve matching to calculate all kinds of parameters. And there was a basic assumption of some fracture geometry. And the technique worked very well. I'm going to give you the final equations for it. The only problem with the technique, as you're going to see, that if you deviate from ideal, ideal"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a90fc6-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "I'm going to give you the final equations for it. The only problem with the technique, as you're going to see, that if you deviate from ideal, ideal would not tell you why. So in the original technique, without going through the detail of derivation, we do that when we teach a graduate class actually. He developed, Nolte did develop the small g function, which he said, well, this is what you would observe. And that delta is basically dimensionless time. Is when you have a high leak off versus low leak off. And then decided to continue working with the high leak off and then decided to continue working with the high leak off case, saying my G function is, which is capital G now, this is essentially the pressure drop. G function is nothing but dimensionless pressure drop. It is function of this lower G function and we people have used this equation here this is lower case G rather rather than the one raised to power 3 over 2 rather than this equation. And once you do that you end the"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91066-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "equation here this is lower case G rather rather than the one raised to power 3 over 2 rather than this equation. And once you do that you end the same, this is my equation here. This is very much like what you see in world testing. So I know g function, dimensionless pressure is function of dimensionless time, and the definition of that g, definition of the G function is here. So it is function of height, a constant that depends on the fluid, the Delta P and I'm going to describe you what Delta P is, it's a little different definition than you are used to, if you've done some more testing. A leak off coefficient, then this is the pay zone. So this is height of the fracture versus height of the pay zone where the fluid is leaking off. And so HP is where fluid is leaking off. E prime is like, if you remember what we discussed is Young's modulus divided by one minus square of Poisson's ratio. And the square root of T, that is my injection time. Okay. So if I use this equation I can"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91106-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "modulus divided by one minus square of Poisson's ratio. And the square root of T, that is my injection time. Okay. So if I use this equation I can actually, it's not difficult to create a curve like, a bunch of curves like this. Well now he has reference time. You look at the equation before, g at some, this is dimensionless time and this is reference time. Okay. And delta P is the difference in pressure relative to reference time. I will describe it in a minute if you want to use it in a problem. So they basically in the original paper by Nolte he used the reference time of 0.25. So for example, if my injection time is 20 minutes, reference time of 0.25 is quarter of that 20 minutes, which is five minutes. So this would be like for five minutes, 10 minutes, 15 and 20. So, he used use the reference, dimension of surface time of 0.25, 0.5, 0.75 and one. And you, once you do that, it's, if you use the equations we just in the previous slide, you can build those curves. So I can, you can"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a911a6-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "0.75 and one. And you, once you do that, it's, if you use the equations we just in the previous slide, you can build those curves. So I can, you can build what the curve for 0.25, 0.5, 0.75, 0.5, 0.75 and 1. So it's very easy to build this graph and you plot this data versus delta, which is your dimensionless time. So you can see right away, just to attract your attention, obviously the first reference time is 0.25, you don't have data below 0.25. If it's 0.5, you can don't have data below 0.5. So that's the reason the curves go this way. And so if I, let me see if I probably did not, I probably should have added another graph to show you. So anyway, I can get my data points like this and you can put them very much like what he borrowed these techniques from world testing, if I match the data, the measured data versus the theoretical data, if I match them, then I could pick a match point, which he picked a point where G, the capital G, the initial pressure, is equal to 1 one and pick"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9123c-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "if I match them, then I could pick a match point, which he picked a point where G, the capital G, the initial pressure, is equal to 1 one and pick stuff from the other curve that you called it P star. This is nothing to do with P star you use in well testing, if you are familiar with well testing. Absolutely nothing to do with it. P star in well testing is extrapolation of pressure and maybe average, close to average reservoir pressure. Here it is nothing but a match point corresponding to dimensionless pressure of 1. And so once you do that, once you get P star, here is P star, so this is, North is P star. Once you, you get it, you substitute in this equation, I get Lykov coefficient. So hopefully I know when, I know the heights and I know BS, this is just a constant here depending on N prime. If you remember we talked about fluids last time. So the flow behavior index. And so that I know, I know, hopefully you know Young's modulus and I know P star. I calculate the Lyakhoff"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a912dc-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "last time. So the flow behavior index. And so that I know, I know, hopefully you know Young's modulus and I know P star. I calculate the Lyakhoff coefficient. Once I do that, I can go in here, calculate rho. Again, this is corresponding to one another. So if I put this one, this would be P star, and I pick ISIP. I can calculate rho. From rho I get efficiency, fraction efficiency, I calculate fraction length, I calculate fraction width, so everything would, would work well. Okay? Okay, the, the, let me go back to this graph and look at, look at it. So I'm, here we're matching four curves. And you notice that it's very rare that you can match the four curves with the theoretical, with the real data, with the theoretical data. And so you do your best to match, but like here, for example, I see deviation at the beginning, that looks good here, it looks good here, then there's deviation at the end. So that technique does not tell me where there is deviation. So if the deviation are"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91386-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "here, it looks good here, then there's deviation at the end. So that technique does not tell me where there is deviation. So if the deviation are extreme, you can look at it and say, this may not be useful enough. Okay? So, so people have started looking at it, although it's extremely valuable, they wanna see how to make it even more valuable, to become more useful and to identify all problems that you may see. So people have looked at multiple issues. One issue for example is temperature change. If you're running a test on a very hot formation, and you're monitoring pressure, in a few cases in South Texas, we observed that actually pressure went down and then it started going up again. Well, that does not exactly agree with the theory. So, one thing, I did this work some time ago when we found out that, because pressure is increasing without that is probably due to temperature changes. So we started running tests and observing, measuring not just the pressure, but measuring"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9141c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "without that is probably due to temperature changes. So we started running tests and observing, measuring not just the pressure, but measuring temperature as well. And we saw the increase in temperature. So we developed the technology to correct for pressure, the effect of temperature on pressure. We're actually applying that similar technology as well as newer technology, obviously, developing technology for ... working on ... geothermal wells. We're... we're starting to analyze wells and geothermal reservoirs where obviously ... the fraction fluid is heating up very much and we observe that same problem. very much and we observe that same problem. And so, another effect is when you have natural fractured formation. So, how you identify what is going on? So, there was an interesting people I referred to earlier by Maharjee and ... and Barry. Margie and Barry. So let's look at their equation. Very, very interesting equation. If you, what they did is if you look at at g function"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a914bc-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "and Barry. Margie and Barry. So let's look at their equation. Very, very interesting equation. If you, what they did is if you look at at g function definition, looks that is, that is what Nolte has developed. that is, that is what Nolte has developed. So if you take the derivative, the derivative of pressure with respect to g function, you end the equation like this, then if you say I'm going this by g function. So I multiply here by g, multiply here by g, I end with this equation. And I say, well, if I plot g dp dg versus g function, what should I get? I should be, I should get a straight line going through the origin. You see, the slope of the straight line is here. So the slope of the straight line will give me the leak-off coefficient. So in order to have analyzable data, I need to see with GDPDG versus G-function, I would need to see a straight line going through the origin. So you look at data. data here this is g function this is the gdpdg sitting on secondary axis but you can"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9155c-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "a straight line going through the origin. So you look at data. data here this is g function this is the gdpdg sitting on secondary axis but you can see it is going through basically is going through the origin this is a almost ideal case and so I'm seeing pressure decline, there is fluctuation here, and I see a pressure fluctuation here. As long as we see fluctuation, we need to talk about it a little bit. This is, this fluctuation is nothing but ... essentially water hammer. If you do not know what water hammer is, think about it this way. If I have a fluid say in a very large tank and going through a pipe, where like, like almost connecting to a faucet, like, almost connecting to a faucet. And, when I shut down that faucet, or fluid does not know that it, that the, that water had stopped. So, it actually continues to move, the water continue to move, compressing the, the fluid or the liquid at that faucet, at that closure. ... So it increases, goes above original pressure, then it"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a915fc-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "to move, compressing the, the fluid or the liquid at that faucet, at that closure. ... So it increases, goes above original pressure, then it flows back, since pressure had increased there, it has to flow back into the tank, and it keeps going back and forth, and every time the signal decays, till it disappears. So, obviously you do not, you do not see it in your house, although, although even in ... in a house, it could happen. ... Sometimes, if pipes are not held in place, you, you shut down, you shut down ... a faucet, and you hear rattling on pipes. That's exactly the same thing you have here in Water Hammer. It's, there was a test that we did work on and it's a hydraulic impedance testing, was essentially based on this idea by imposing a drop in pressure and observing the signal going through downhole into a fracture, then reflecting back. So, usually when you see water hammer, is an indication of very tight formation. Because if, if, if the formation probability is very high,"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9169c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "back. So, usually when you see water hammer, is an indication of very tight formation. Because if, if, if the formation probability is very high, then the damping is, is very high too. So you, you don't see that fluctuation. That fluctuation is when you use liquid, and when you have a tight formation. There is techniques to analyze water hammer. And some of them like hydraulic impedance testing, I... I wrote it, there was some work done on the subject several years ago, I... more than 20 years ago, and actually I wrote a paper on subject, where we applied it to calculate fraction length. It's a very interesting technique. But, important thing here, so that does not, the presence of water hammer, does not disqualify the technique we're applying here. So, you can see, you see very nice straight line. So, this is, this is essentially, almost an ideal case. So, if I see situation like this, I can take the slope like this is intersecting the origin, you have a straight line, I can"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9173c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "almost an ideal case. So, if I see situation like this, I can take the slope like this is intersecting the origin, you have a straight line, I can calculate very much a calculate Lekhov coefficient from that slope. And I can come here and say that this is normally curve there is nothing extraordinary. Okay now there are cases where people have observed when you plot the g function it goes up and then it's flattened out and flattened down then it's eventually follows a straight line. And if I draw the straight line going through the origin, I can calculate leak of coefficient in the formation here. And the ending there, this is where the fracture closed. So, what is going on here? Well, this is at high pressure. If you have natural fractures, basically what we're talking here, fissures, natural fractures existing, you open up those natural fractures, so you have very high leak off into those natural fractures. As the pressure, you see the pressure is declining this way. Well, G-unction"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a917dc-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "fractures, so you have very high leak off into those natural fractures. As the pressure, you see the pressure is declining this way. Well, G-unction is increasing. As the pressure declines, those fissures start closing. Eventually, this would, the natural fracture close, but the fracture itself, the hydraulic fracture is still open. So the natural fractures are closed at a higher pressure than the hydraulic fracture, because they're not in the same orientation, basically. So you can, so that here, not only I can get the leak off coefficient from here, but I can say, hey, I have also natural fractures. So that became this, when you see such a behavior, you can diagnose it. Well, sometimes you actually see the reverse behavior. And so you're seeing that eventually follow a straight line that goes through the origin but in the area here I don't have that straight line. So I can calculate the Lekow coefficient here from the formation from this area, but in the earlier area, it usually"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91872-8642-11ee-a37b-0242ac1c000c
encoding: FLOAT32
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "I don't have that straight line. So I can calculate the Lekow coefficient here from the formation from this area, but in the earlier area, it usually interpreted as, the, the fracture is losing, is losing height. And so, if I, if I calculate leak off coefficient from here is, from that early part, that's, that's not work very well. part of this, does not work very well. It's ... another, another ... another area, that or shape that you may see, is where, when you find, here in this specific case, this is a very tight formation, because you have really high, you have a very high water hammer, you can see very sharp water hammer, where pressure has been fluctuating. You look at it here, very severely, and not only that, for a fairly long time. That's an indication of very tight formation. In very tight formation, if I'm, if my, the leak off is, is very small, if the leak off is very small, ... maybe the pressure will equalize inside the fracture, and it stays inside the fracture, at a"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a9191c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "is, is very small, if the leak off is very small, ... maybe the pressure will equalize inside the fracture, and it stays inside the fracture, at a higher than fracturing pressure for some time. So, what happens when the fracturing, the fluid pressure inside the fracture, it stays for some time above fracturing pressure? When, what happens is, and without leaking off, very much, very little leak off, the fracture will continue to propagate, even after you stop injection. And, you can see in this case, when you draw that straight, you draw that straight line, the straight line never ended in this case. Has not ended yet, so your fracture has not closed yet, and you can see it does not intersect the origin, the zero and zero. So, it's sitting above zero and zero. So I, that leak of coefficient, the closure time obviously is very long and fracture has not closed yet. And the, the fracture tip extension after end of injection combined with the water hammer that we're seeing here, it tells"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "has not closed yet. And the, the fracture tip extension after end of injection combined with the water hammer that we're seeing here, it tells me that the formation is extremely tight. It may not be even be productive. There was a lot of newer technology that came up afterwards. The first attempt to calculate permeability was by Mayer Hoffer. I should have put his reference here. as referenced here. And basically, they try to do superposition and calculate fracture length, and formation permeability, especially formation permeability from before closure, rather than calculating leak-off coefficient. before closure rather than calculating leak-off coefficient. Then the issue with that original technique, although it's a very smart idea, the issue with it was you have to be very close to the right solution in order, if it was an iterative technique, in order for those iterations to converge. So you, so that was a problem. Valco and Economidis came back and they published a very"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91a5c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "technique, in order for those iterations to converge. So you, so that was a problem. Valco and Economidis came back and they published a very interesting paper, they, they presented a very good technique for calculation of formation permeability. So it is update over Mayor Hafer and the Economists, Michael Economists. Then we saw an issue with it, there was some issues with the technique, with oversight in some of the definitions, so we have corrected that, and Lamy and I published a paper on the subject. So I would advise you to, if you apply VALCON to convey this technique, please read the paper by Elami and I, because you need to consider that correction. It's an oversight on VALCO and the Convenience, or maybe in typing. Then we published another technique that came up in 2014, where we can ... Sadiq and I, we went through, rather than going, I may show you a question from Valko, and we can read this in a minute, or, or it's going to be on the slides that I will put in, on"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91afc-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "than going, I may show you a question from Valko, and we can read this in a minute, or, or it's going to be on the slides that I will put in, on ResearcherGate. Rather than going through the superposition way of, and depending on the fractioning equations, what we did, we developed Sadiq and I, Sadiq in his PhD dissertation, he developed the equation rigorously of fluid flow with fracture propagation, and based on pressure decline, and we, we came up with a technique, that rather than calculating permeability, we, it calculates fracture dimensions, fracture size. So fracture area. So it, it requires, it requires maybe, what combining the technique either with Valkyrie's technique or with after closure technique that we'll describe in a second. ... There is a recent ... approach by McClure, it's not for formation probability, but basically for ... closure pressure. ... Closure pressure, there is a lot of controversy, how high or how low it is and, ... so McClure found, he developed"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91b9c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "for ... closure pressure. ... Closure pressure, there is a lot of controversy, how high or how low it is and, ... so McClure found, he developed developed an approach based on, on fracturing. And, he predicts that, that, that closure pressure is a lot higher than what you get from G-Function. We, another technique that was ... been developed and being developed, we are using, this we are doing it at ... UH. We used the wavelet transform ... to, to calculate closure pressure. ... wavelet is, is a, is a, is an approach, or it's data signal analysis basically. ... And it maintains the, or tell you the discontinuity, or the issues with, with the signal, ... when it maintains the, the location and time. So when we applied it, we actually we find out that closure pressure in many cases is indeed higher than what G-Function would predict. So it happens earlier in time, but it's not as high as what McClure has published. We are having a paper in, coming in February, where we are going to"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91c32-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "it happens earlier in time, but it's not as high as what McClure has published. We are having a paper in, coming in February, where we are going to compare the, the various techniques. ... For after closure analysis, for permeability, there is two basic technique, well actually there's several techniques, but to me they are, the basic techniques are the one developed by Nalti and the one I, I published back in 2005, but we upgraded the technique later on. ... Essentially, Nour... was noticed technique, he's look at it saying, I have a constant pressure injection and I either have radial flow or linear flow. And ... it, it works, it works okay, but I think what we, what we are, what we presented in ALMA is a little different approach. Rather than saying is a constant pressure, we look at it as a total volume that was injected, since it's over a shorter time than the, than the, than the after closure time, or actually after injection time. And if you, if you look at it that fashion, and"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91cd2-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "a shorter time than the, than the, than the after closure time, or actually after injection time. And if you, if you look at it that fashion, and put the equation together, you end up finding an approach where, when you plot the data the way we are saying here in the paper in 2005, you can tell whether you have linear flow, radial flow, bilinear flow, or even spherical flow. Actually, we have seen all those flow regimes. But, so that, the technique actually, the advantage of it, rather than you try to find a certain slope, or you plot it, you make assumption of the slope, or of the flow regime, the technique first, the first graph graph tells you what flow regime you have and based on that flow regime you continue, so you... you move from determining the flow regime into different direction depending of what flow regime you have and you can then from there you calculate formation, permeability and so on and so forth. The... when we... then we ended developing looking at ... dual"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91d7c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "you can then from there you calculate formation, permeability and so on and so forth. The... when we... then we ended developing looking at ... dual porosity model. ... Because, once we got into shale, we start observing that the behavior is different, so we... we developed ... a couple of techniques, the first techniques with, with observation of the dual porosity model with people, with published in 2009, then with one of my students, Elwaziri, he did very good piece of work on, on dual porosity model where we developed the equation to describe the model in a special way and this way we could analyze the data and we tell formation properties. That is basically the end of this lecture. I'm going to... there is ... to go into other techniques in details, maybe this is something we can do it in the future in a special presentation, but it would require knowledge of well testing to get into more details of testing. So now we'll... Okay, so thank you, doctor, for this informative"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91e1c-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "but it would require knowledge of well testing to get into more details of testing. So now we'll... Okay, so thank you, doctor, for this informative session. Now we will begin by addressing some questions. The first question is that from the well-testing techniques we have today, what are the most common techniques used in fracturing shale plates? Say it again, the most common technique, well-testing, what did you do in well-testing? Yes, we have some well testing techniques today. What are the most commonly ones, common ones we see in while fracturing shale plates? A common technique for analysis of data or fracturing itself? He didn't mention but I think analysis. Dr. Salman, I believe the question is, do we use the same well testing techniques we had today in the lecture in fracturing shale plates? Well, that's a very good question. I don't, some people do, I don't advise using exactly the same techniques because shell is naturally fractured, that's number one, is extremely tight"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91ebc-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "I don't, some people do, I don't advise using exactly the same techniques because shell is naturally fractured, that's number one, is extremely tight and I have seen people, some people using the will testing techniques blindly. I think that's a bad idea. We've published some papers that goes into details of that and describes. I have especially a review paper in Elsevier that goes into testing of shale in details. And it's a review paper so it goes into a bunch of things. I did not refer to it here, but I would advise the person that asked this question to read that paper, because applying well-testing techniques to defeat applying well-testing techniques to defeat blindly can give you questionable results. Okay, thank you. And the last question for today is that what is... Just one second. I'm going to put... I can't put the paper itself in the presentation because it's a copyrighted, you know, once you publish a paper it's copyrighted, you can't, but I'm going to put the reference"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91f52-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "in the presentation because it's a copyrighted, you know, once you publish a paper it's copyrighted, you can't, but I'm going to put the reference in it and maybe a couple of sentences so you have to get the paper on your own. you, you have to get the paper on your own. Yes, yes. Okay, so the final question for today is that, what is a good software that can be used for well testing, hydraulic, hydraulic fractured wells? it was? I cannot recommend software that is a commercial thing to there's a lot of software that are good I can't I cannot be endorsing a software. We at University of Houston, we have multiple software that we use for analysis of data, as well as we have developed our own software to do certain things that are not used. For example, a wavelet analysis that we developed our own software to do it. And we give it to companies that sponsoring our research. Some of the analysis technique, we developed a spreadsheets to do it since we want to do it a little differently."}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a91ff2-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "that sponsoring our research. Some of the analysis technique, we developed a spreadsheets to do it since we want to do it a little differently. But several companies have software, they are all very good. I have to decline answering this more than that. Yes, yes, I understand. Thank you. And I have to decline answering this more than that. Yes, yes, I understand. Thank you. Thank you again for the time you have dedicated for delivering this course. And as a reminder, don't forget to do the last quiz for this course and do the final exam, which will be held on Tuesday, the 3rd of November, 2 p.m. Egypt time and also 8 p.m. Egypt time. And also we have another exam Wednesday, the 4th of November, 2 a.m. Egypt time. However, you can only do one final exam with that We have came we have come into a to end and the best of luck and Have a nice day and see you in future webinars. Thank you. Well, thank you everyone and If you if you have Special question Don't hesitate to send me an email at"}


created_at: 2023-11-18 18:50:12
topic: persistent://default/default/8e5da3e9-8391-4ad8-a826-4d5919dbf381
id: c2a92088-8642-11ee-a37b-0242ac1c000c
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{"source": "./Hydraulic Fracturing Technology, Dr. Mohamed Soliman, University of Houston - 04-04.txt", "chroma:document": "day and see you in future webinars. Thank you. Well, thank you everyone and If you if you have Special question Don't hesitate to send me an email at mysolomon.uh.edu. And thanks everyone."}


