Unconventional hydrocarbon resources are the future of the fossil fuel industry and the priority targets for development in North America. These resources include heavy oil from oil sands and carbonates, light-tight oil and liquid-rich shale. The main challenge of extracting these resources is that the hydrocarbon mobility in the reservoir is very low, requiring advanced, unconventional extraction methods.
In-situ heavy oil recovery has several advantages over ex-situ processes such as avoidance of mining costs, no solid waste disposal, potentially lower costs, and access to resources, etc. The conventional in-situ method to extract heavy oil/bitumen faces several challenges such as difficulties in establishing required fluidity, permeability, porosity, and possible contaminations, etc. Moreover, steam assisted gravity drainage (SAGD) or cyclic steam stimulation (CSS), the most commonly used in-situ extraction technologies, require a significant amount of energy to generate high quality steam while simultaneously ignoring associated greenhouse gas (GHG) emission. Accordingly, there have been growing demands for new technologies that are relatively more cost-effective, efficient, and environmentally friendly. The present invention surpasses the limitations of SAGD or CSS technology and responds to the call for better oil recovery technology. In recent years, the use of radio frequency (RF) or electromagnetic (EM) waves to heat heavy oil to lower viscosity has been considered as an alternative or an upgrade to SAGD or CSS technology.
In fact, EM radiations neither require steam nor heavy infrastructure to generate and pump steam into underground oil formations using thick pipes. The EM waves are generated by passing high-power electric signals of varying frequencies through antennas that are inserted along with the producer wells or horizontal pipes in underground oil formations. The effectiveness of EM waves to heat a target is inversely proportional to the distance of the target from the antenna but directly proportional to the target's permittivity or absorption of incident EM waves. EM waves typically attenuate with the inverse square or cube of the distance from the antenna, losing power rapidly when it is farther away from the antenna.
Also heavy oil/bitumen itself is a poor absorber of EM waves on account of its low permittivity. As it is heated over time, the permittivity or absorptivity of heavy oil/bitumen does not stay constant; however, it varies with temperature and viscosity.
As a result, the efficiency of existing EM heating techniques can diminish on the basis of heavy oil/bitumen's geological vicinity with respect to the antenna and their thermophysical properties.
Even with advanced technologies such as EM or RF radiation enhanced recovery, SAGD, CSS and electro-thermal dynamic stripping (ET-DSP™), unconventional hydrocarbon recovery is relatively expensive in comparison with the extracted crude oil from other parts of the world and the impact of extraction and processing methods on the environment is significant.
Accordingly, responding to the growing demands for reduction of water and energy usages and minimization of GHG emission is of great importance.
Enhanced Oil Recovery (EOR) and Upgrading
US 2014/0251607 to DOW Global Technologies discloses methods using a nonionic surfactant for EOR, where the nonionic surfactant is prepared with a double metal cyanide catalyst. The nonionic surfactant can be used as part of foam for use in EOR. An example of such foam includes the nonionic surfactant, carbon dioxide in a liquid or supercritical phase, and a diluent, where the nonionic surfactant promotes a formation of the foam formed of carbon dioxide and the diluent.
US 2014/0209304 to Ecolab USA Inc, discloses water-soluble polymers comprising hydrolysable cross-linked monomer units, and methods for recovering hydrocarbon fluids using aqueous flooding of a formation. The polymer comprising about 1 mol % to about 100 mol % acrylamide monomers, wherein, after introducing the aqueous flooding fluid into the formation, the hydrolysable cross-linked monomer units are hydrolyzed to produce an aqueous flooding fluid after hydrolysis having a viscosity that is about the same or higher than a viscosity of the aqueous fluid prior to injection.
US 2010/0175896 to BP Corp. North America Inc, teaches methods and compositions for catalytic heavy oil recovery. The novel colloidal catalysts are utilized, which may catalyze hydrogenation reactions in heavy oil deposits. These colloidal catalysts may be dispersible in supercritical fluids, which are also injected into the reservoir.
U.S. Pat. No. 3,408,417 teaches a method for thermal cracking of hydrocarbons including introducing combusting gases and hydrocarbons into a first zone, the latter at a speed of sound or greater, then passing the thereby mixed resultant through a constriction at the speed of sound or greater into a second zone for thermal cracking purposes, then quenching the reactants with a coolant.
US 2013/0168295 top FL Smith discloses different types of cracking employed: catalytic cracking and thermal cracking. Catalytic cracking uses a solid acid catalyst, such as aluminum oxide and silicon dioxide, in moderately-high temperatures to aid in the process of breaking down large hydrocarbon molecules into smaller ones. In thermal cracking, elevated temperatures and pressures are used to break the long chain alkanes down into shorter chain alkanes and alkenes. The catalyst serves to semi-crack the oil sands or oil shale during the retort step by breaking down long hydrocarbon chains to shorter chains. The preferred catalysts are zeolite catalysts, which provide high yields and selectivity for hydrocarbon fuel with higher-boiling point.
US 2013/0168094 to ConocoPhillips Company discloses methods and systems for enhanced recovery of heavy oil using selective catalyst downhole upgrading scheme in combination with SAGD technology. The method provides a cracking catalyst and then heats the cracking catalyst to a catalyst pre-heated temperature. Examples of suitable cracking catalysts include high surface area catalysts, such as nanocatalysts.
Microwave Based Methods
U.S. Pat. No. 8,337,769 to Harris Corp. teaches a method to heat petroleum ore, such as bitumen, oil sands, tar sands, oil shale, or heavy oil by mixing about 10% to 99% by volume of a substance such as petroleum ore with about 1% to 50% by volume of a substance comprising mini-dipole antenna susceptors. A mini-dipole susceptor is defined as any susceptor that reacts as a dipole antenna to RF energy, and which has a longest dimension less than 10 cm, 5 cm, 1 cm, or 0.5 cm. In this disclosure, thin filament-like conductive structures such as carbon fibers are distributed through the hydrocarbon ore as susceptors. The mixture of petroleum ore and mini-dipole susceptors is then subjected to an RF energy source to create heat.
U.S. Pat. No. 4,419,214 describes a method of separating bitumen and tars from shale oils and tar sands through the use of microwave treatment.
U.S. Pat. No. 4,153,533 teaches recovering oil from shale through microwave irradiation of feedstock under high pressure and in the presence of hydrogen and water vapor.
US 2013/000865 to ConocoPhillips Company teaches a method for more efficiently recovering hydrocarbon resources from a subterranean formation and while potentially using less energy and/or water resources and providing faster recovery of the hydrocarbons. Recovering hydrocarbon resources from infill wells based upon RF heating may comprise creating hydraulic communication between each pair of adjacent steam chambers and an associated infill well there between. Moreover, recovering hydrocarbon resources from the infill wells based upon RF heating may further comprise using SAGD to provide pressure support in the regions of the subterranean formation surrounding the infill wells.
U.S. Pat. No. 8,646,527 to Harris Corp. discloses use of a RF applicator to produce electromagnetic energy within a hydrocarbon formation where water is present near the applicator. A signal, sufficient to heat the hydrocarbon formation through electrical current, is applied to the applicator. The same or alternate frequency signals are then applied to the applicators that are sufficient to heat the hydrocarbon formation through electric fields, magnetic fields, or both.
U.S. Pat. No. 8,726,986 to Harris Corp. teaches a method for heating a hydrocarbon resource in a subterranean formation having a laterally extending wellbore. The method includes supplying RF power at a settable frequency from an RF radiator positioned within the laterally extending wellbore to heat hydrocarbon resource and start formation of a steam bubble adjacent the laterally extending wellbore, and while sensing an impedance matching value of the RF radiator.
US 2012/0234536 to Harris Corp discloses a method for heating heavy oil inside a production well by utilizing an activator. The activator is then excited with a generated non-microwave frequency from 0.1 MHz to 300 MHz. A catalyst is injected below the surface such that the catalyst contacts the heated heavy oil. The catalyst can be co-injected with the activator, pre-injected or injected after the initial heating. The suitable activators discussed in the invention are the same as those from U.S. Pat. No. 8,365,823. Catalysts may comprise organometallic complexes and peroxides.
Microwave/RF Based Sensitizers and Treatments
US 2004/0031731 discloses the use of microwave irradiation to extract hydrocarbon fuel from oil sand or shale. The method includes admixing the oil sand or shale with a sensitizer and then exposing it to microwave energy. Suitable sensitizers include activated carbon and metal oxides such as NiO, CuO, Fe3O4, MnO2, Co2O3, and WO3. The catalysts can be metal powder such as a para-ferromagnetic material, iron, copper, or nickel. The concentration range is approximately 0.5 to 10 wt % based upon the weight of the fuel oil being processed. The sensitizers and catalysts used in this invention are disclosed in U.S. Pat. No. 6,184,427.
US 2012/0138601 discloses a method and apparatus for the continuous processing of high molecular weight organic feedstock material. Sensitizers may be heated by microwave energy, and the feedstock material, sensitizer material and catalyst, may undergo reactions such as de-polymerization, olefin oligomerization, dehydrogenation, isomerization, naphthene ring formation, aromaticization and chain branching.
U.S. Pat. No. 8,365,823 to ConocoPhillips Company discloses a method for heating heavy oil by utilizing an activator. The activator is excited with a generated microwave frequency and heats the heavy oil. Activators include ionic liquids that may include metal ion salts and may be aqueous and inorganic anions such as halides. The activator could be a metal containing compound such as those from period 3 or period 4. In yet another embodiment the activator could be a halide of Na, Al, Fe, Ni, or Zn, including AlCl4−, NiCl3−, ZnCl3− and combinations thereof. Other suitable compositions for the activator include transitional metal compounds or organometallic complexes. The more efficient anion is at coupling with the microwave/RF radiation the faster the temperature rise in the system.
U.S. Pat. No. 6,184,427 to Invitri Inc. teaches microwave and radio frequency irradiation in order to crack hydrocarbons and waste plastics into smaller molecular weight entities. Microwave activated cracking of liquid hydrocarbons usually requires a catalyst/sensitizer. The sensitizer used in the invention exhibits high dielectric loss at microwave and radio frequencies. The sensitizer may be activated carbon (pellets or powder), coal, transition metal oxides such as NiO, CuO, etc. The catalysts are obtained by impregnating a high surface area support material such as silica, y-alumina, Zeolite, activated carbon, etc.
U.S. Pat. No. 6,861,135 to Kimberly-Clark Worldwide Inc teaches a latent polymer composite which contains a heat-sensitive polymer material and a microwave sensitizer. Polymer materials useful as the latent polymer material include thermoplastic elastomers and Exxon 601, which is a proprietary polymer comprising from about 20 to about 30% by weight olefinic elastomer, from about 60 to 75% by weight ethylene copolymer, from about 4 to 10% by weight processing oil, and less than about 5% by weight other additives. Other useful polymer materials include ethylene-vinylacetate block or random copolymers, polyethylene-polyethylene oxide block copolymers, polypropylene oxide-polyethylene oxide block copolymers, polyesters, polyurethanes, polyacrylates, polyethers, and combinations thereof. Sensitizer materials useful in this invention include calcium chloride, carbon black powder, metal particles, metal oxides such as aluminum, copper, zinc, and their oxides, various ferrite containing materials such as barium ferrite and magnesium ferrite, magnesium acetate, and combinations thereof.
U.S. Pat. No. 6,797,126 to Reactive Energy LLC. teaches a method of desulphurizing and cracking fuel oil by mixing the fuel oil with a sensitizer and solid source of hydrogen to form an admixture followed by subjecting the admixture to microwave energy. The sensitizers and catalysts discussed are the same as those from US 2004/0031731. Desulphurizing additives are used, and they may consist of granulated limestone and other forms of CaCO3, CaO, MgO, MgO—CaO, NaOH, KOH, and NaHCO3.
Heat Activated Chemical Reaction Giving off Gas/Chemical Blowing Agents (CBAs)
U.S. Pat. No. 4,769,397 to Enron Chemical Company discloses a method of making a foam injection molded article, and dispersing an effective amount of a primary CBA into a polymer resin to form a mixture. The mixture is then heated whereby the activation system releases water and the sodium borohydride reacts with the water to produce hydrogen gas. Subsequently, the mixture is injected into a mold to obtain expansion of the polymer resin into a molded foam article.
U.S. Pat. No. 7,543,638 to Schlumberger Technology Corp. teaches placing a catalyst in a wellbore; and introducing an oxidizing agent into the wellbore to contact the catalyst such that a hydrocarbon in a formation is oxidized to produce heat and at least one gas. The catalyst may be one selected from platinum, palladium, rhodium, ruthenium, lead, manganese, nickel and metal oxides thereof.
All of the above mentioned methodologies typically require undesirably large quantities of water. It is therefore an object of the present invention is to provide methods for enhancing heavy oil/bitumen extractions and in-situ upgrading from oil sands, tight oil, oil shales, carbonates and where hydrocarbons are present.