for acquisitions of properties with additional development , exploitation and exploration potential , we have focused on acquiring properties that we expect to operate so that we can control the timing and implementation of capital spending . in some instances , we have acquired non-operated property interests at what we believe to be attractive rates of return either because they provided an entry into a new area of interest or complemented our existing operations . we intend to continue to acquire both operated and non-operated properties to the extent we believe they meet our return objectives . in addition , the acquisition of non-operated properties in new areas provides us with geophysical and geologic data that may lead to further acquisitions in the same area , whether on an operated or non-operated basis . due to the geographic concentration of our oil and natural gas properties in the williston basin , we believe the primary sources of opportunities , challenges and risks related to our business for both the short and long-term are : commodity prices for oil and natural gas ; transportation capacity ; availability and cost of services ; and availability of qualified personnel . our revenue , profitability and future growth rate depend substantially on factors beyond our control , such as economic , political and regulatory developments as well as competition from other sources of energy . oil and natural gas prices historically have been volatile and may fluctuate widely in the future . crude oil prices have declined significantly since mid-2014 . as a result of sustained low oil prices , we have decreased our planned 2016 capital expenditures as compared to 2015 , and we are continuing to concentrate our drilling activities in certain areas that are the most economic in the williston basin . extended periods of low prices for oil or natural gas could materially and adversely affect our financial position , our results of operations , the quantities of oil and natural gas reserves that we can economically produce and our access to capital . prices for oil and natural gas can fluctuate widely in response to relatively minor changes in the global and regional supply of and demand for oil and natural gas , as well as market uncertainty , economic conditions and a variety of additional factors . since the inception of our oil and natural gas activities , commodity prices have experienced significant fluctuations . the current global oversupply of crude oil has caused a sharp decline in oil prices since mid-2014 . we enter into crude oil sales contracts with purchasers who have access to crude oil transportation capacity , utilize derivative financial instruments to manage our commodity price risk and enter into physical delivery contracts to manage our price differentials . in an effort to improve price realizations 48 from the sale of our oil and natural gas , we manage our commodities marketing activities in-house , which enables us to market and sell our oil and natural gas to a broader array of potential purchasers . due to the availability of other markets and pipeline connections , we do not believe that the loss of any single oil or natural gas customer would have a material adverse effect on our results of operations or cash flows . additionally , we sell a significant amount of our crude oil production through gathering systems connected to multiple pipeline and rail facilities . these gathering systems , which originate at the wellhead , reduce the need to transport barrels by truck from the wellhead . as of december 31 , 2015 , we were flowing over 80 % of our gross operated oil production through these gathering systems . please see “ item 1. business—marketing , transportation and major customers . ” our quarterly average net realized oil prices and average price differentials are shown in the tables below . replace_table_token_14_th replace_table_token_15_th replace_table_token_16_th ( 1 ) realized oil prices do not include the effect of derivative contract settlements . ( 2 ) price differential reflects the difference between realized oil prices and wti crude oil index prices . changes in commodity prices may also significantly affect the economic viability of drilling projects as well as the economic valuation and economic recovery of oil and gas reserves . crude oil produced and sold in the williston basin has historically sold at a discount to wti due to transportation costs and takeaway capacity . in the past , there have been periods when this discount has substantially increased due to oil production in the area increasing to a point that it temporarily surpasses the available pipeline transportation , rail transportation and refining capacity in the area . recent expansions of both rail and pipeline facilities have reduced the prior constraint on oil transportation out of the williston basin and improved netback pricing received at the lease . in early 2013 , our average price differentials relative to wti narrowed , primarily due to our ability to access premium coastal markets by rail . as the premium received in coastal markets contracted during the second and third quarters of 2013 , our average price differentials relative to wti increased . in the fourth quarter of 2013 and into the first quarter of 2014 , our average price differentials relative to wti continued to increase due to the pipeline market weakening as a result of refinery down time and increased u.s. and canadian production . in the second and third quarters of 2014 , stronger pipeline prices shifted more of our barrels towards the pipelines , but rail buyers had to compete with pipeline prices despite weaker brent differentials , resulting in price differentials relative to wti of approximately 9 % to 11 % . story_separator_special_tag 52 expenses and other income the following table summarizes our operating expenses , gain on sale of properties and other income and expenses for the periods presented : replace_table_token_18_th ( 1 ) for the year ended december 31 , 2013 , lease operating expenses include midstream income and operating expenses , which are included in well services and midstream revenues and well services and midstream operating expenses , respectively , for the years ended december 31 , 2015 and 2014. year ended december 31 , 2015 as compared to year ended december 31 , 2014 lease operating expenses . lease operating expenses decreased $ 25.1 million to $ 144.5 million for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 . this decrease was primarily due to lower workover costs and an increase in salt water disposal volumes being transported on oms pipelines and injected in oms salt water disposal wells , partially offset by higher costs associated with operating an increased number of producing wells . we completed and placed on production 64.3 total net wells in the williston basin during the year ended december 31 , 2015 as compared to 151.1 total net wells completed and placed on production during the year ended december 31 , 2014 . lease operating expenses decreased from $ 10.18 per boe for the year ended december 31 , 2014 to $ 7.84 per boe for the year ended december 31 , 2015 due to the lower costs and increase in oil and natural gas production . well services and midstream operating expenses . well services and midstream operating expenses represent third-party working interest owners ' share of completion service costs , cost of goods sold and operating expenses incurred by ows and 53 oms . the $ 22.2 million decrease for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 was attributable to a $ 23.8 million decrease in well completion costs as a result of lower well completion product sales to third parties due to ows completing substantially all of opna 's operated wells , coupled with ows completing opna wells with a lower average third-party working interest in the year ended december 31 , 2015 as compared to december 31 , 2014 . this decrease was partially offset by a $ 1.6 million increase related to midstream operating expenses and fresh water purchases . marketing , transportation and gathering expenses . marketing , transportation and gathering expenses increased $ 2.5 million year over year , or a $ 0.03 decrease per boe , which was primarily attributable to a $ 1.4 million increase in gas gathering charges related to additional well connections on oms infrastructure , a $ 1.4 million increase in oil transportation costs associated with having additional wells connected to third-party infrastructure and a $ 0.3 million increase in our pipeline imbalance . these increases were partially offset by a decrease year over year of $ 0.9 million in the write down of our linefill inventory to the lower of cost or market value at year-end . excluding non-cash valuation adjustments , our marketing , transportation and gathering expenses on a per boe basis would have remained constant at $ 1.62 and $ 1.61 for the years ended december 31 , 2015 and 2014 , respectively . the transporting of volumes through third-party oil gathering pipelines increases marketing , transportation and gathering expenses but improves oil price realizations by reducing transportation costs included in our oil price differential for sales at the wellhead . production taxes . our production taxes for the years ended december 31 , 2015 and 2014 were 9.6 % and 9.8 % , respectively , as a percentage of oil and natural gas sales . the production tax rate decreased slightly year over year primarily due to reduced extraction tax rates triggered by lower oil prices on certain north dakota wells , partially offset by an increased weighting of wells in north dakota , which has a higher average production tax rate as compared to montana . for the years ended december 31 , 2015 and 2014 , the percentage of our total production located in north dakota was approximately 88 % and 86 % , respectively . in 2015 and 2014 , north dakota had a crude oil tax structure based on a 5 % production tax and a 6.5 % oil extraction tax , resulting in a combined tax rate of 11.5 % of crude oil revenues . in 2016 , the north dakota oil extraction tax will be reduced to 5 % , resulting in a 10 % combined tax rate , which will rise by 0.5 % if crude oil prices average above $ 90 per barrel for three consecutive months . depreciation , depletion and amortization ( “ dd & a ” ) . dd & a expense increased $ 73.0 million to $ 485.3 million for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 . the increase in dd & a expense for the year ended december 31 , 2015 was primarily due to an increase in the average dd & a rate per boe year over year coupled with production increases from our wells completed during 2015 . the dd & a rate for the year ended december 31 , 2015 was $ 26.34 per boe as compared to $ 24.74 per boe for the year ended december 31 , 2014 . the increase in the dd & a rate was primarily due to lower recoverable reserves related to lower oil and natural gas prices and increased exploratory and delineation drilling in the three forks formation . rig termination . as a result of our lowered 2015 capital expenditure program , we elected to early terminate certain drilling rig contracts and recorded a rig termination expense of $ 3.9 million for the

net cash provided by financing activities was $ 83.3 million , $ 158.8 million and $ 1,625.7 million for the years ended december 31 , 2015 , 2014 and 2013 , respectively . for the year ended december 31 , 2015 , cash sourced through financing activities was provided by net proceeds from the issuance of our common stock , partially offset by net repayments on our revolving credit facility . for the year ended december 31 , 2014 , cash sourced through financing activities was provided by borrowings under our revolving credit facility . for the year ended december 31 , 2013 , cash sourced through financing activities was primarily provided by the issuance of our senior unsecured notes , borrowings under our revolving credit facility and net proceeds from the issuance of our common stock . sale of common stock . on march 9 , 2015 , we completed a public offering of 36,800,000 shares of our common stock at an offering price of $ 12.80 per share . we used the net proceeds from the offering of $ 462.8 million , after deducting underwriting discounts and commissions and estimated offering expenses , to repay outstanding indebtedness under our revolving credit facility and for general corporate purposes . on february 2 , 2016 , we completed a public offering of 39,100,000 shares of our common stock at a purchase price of $ 4.685 per share . net proceeds from the offering were $ 182.9 million , after deducting underwriting discounts and commissions and estimated offering expenses , which we intend to use for general corporate purposes and to fund a portion of our 2016 capital expenditures . senior unsecured notes .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```net cash provided by financing activities was $ 83.3 million , $ 158.8 million and $ 1,625.7 million for the years ended december 31 , 2015 , 2014 and 2013 , respectively . for the year ended december 31 , 2015 , cash sourced through financing activities was provided by net proceeds from the issuance of our common stock , partially offset by net repayments on our revolving credit facility . for the year ended december 31 , 2014 , cash sourced through financing activities was provided by borrowings under our revolving credit facility . for the year ended december 31 , 2013 , cash sourced through financing activities was primarily provided by the issuance of our senior unsecured notes , borrowings under our revolving credit facility and net proceeds from the issuance of our common stock . sale of common stock . on march 9 , 2015 , we completed a public offering of 36,800,000 shares of our common stock at an offering price of $ 12.80 per share . we used the net proceeds from the offering of $ 462.8 million , after deducting underwriting discounts and commissions and estimated offering expenses , to repay outstanding indebtedness under our revolving credit facility and for general corporate purposes . on february 2 , 2016 , we completed a public offering of 39,100,000 shares of our common stock at a purchase price of $ 4.685 per share . net proceeds from the offering were $ 182.9 million , after deducting underwriting discounts and commissions and estimated offering expenses , which we intend to use for general corporate purposes and to fund a portion of our 2016 capital expenditures . senior unsecured notes .
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 Suspicious Activity Report : for acquisitions of properties with additional development , exploitation and exploration potential , we have focused on acquiring properties that we expect to operate so that we can control the timing and implementation of capital spending . in some instances , we have acquired non-operated property interests at what we believe to be attractive rates of return either because they provided an entry into a new area of interest or complemented our existing operations . we intend to continue to acquire both operated and non-operated properties to the extent we believe they meet our return objectives . in addition , the acquisition of non-operated properties in new areas provides us with geophysical and geologic data that may lead to further acquisitions in the same area , whether on an operated or non-operated basis . due to the geographic concentration of our oil and natural gas properties in the williston basin , we believe the primary sources of opportunities , challenges and risks related to our business for both the short and long-term are : commodity prices for oil and natural gas ; transportation capacity ; availability and cost of services ; and availability of qualified personnel . our revenue , profitability and future growth rate depend substantially on factors beyond our control , such as economic , political and regulatory developments as well as competition from other sources of energy . oil and natural gas prices historically have been volatile and may fluctuate widely in the future . crude oil prices have declined significantly since mid-2014 . as a result of sustained low oil prices , we have decreased our planned 2016 capital expenditures as compared to 2015 , and we are continuing to concentrate our drilling activities in certain areas that are the most economic in the williston basin . extended periods of low prices for oil or natural gas could materially and adversely affect our financial position , our results of operations , the quantities of oil and natural gas reserves that we can economically produce and our access to capital . prices for oil and natural gas can fluctuate widely in response to relatively minor changes in the global and regional supply of and demand for oil and natural gas , as well as market uncertainty , economic conditions and a variety of additional factors . since the inception of our oil and natural gas activities , commodity prices have experienced significant fluctuations . the current global oversupply of crude oil has caused a sharp decline in oil prices since mid-2014 . we enter into crude oil sales contracts with purchasers who have access to crude oil transportation capacity , utilize derivative financial instruments to manage our commodity price risk and enter into physical delivery contracts to manage our price differentials . in an effort to improve price realizations 48 from the sale of our oil and natural gas , we manage our commodities marketing activities in-house , which enables us to market and sell our oil and natural gas to a broader array of potential purchasers . due to the availability of other markets and pipeline connections , we do not believe that the loss of any single oil or natural gas customer would have a material adverse effect on our results of operations or cash flows . additionally , we sell a significant amount of our crude oil production through gathering systems connected to multiple pipeline and rail facilities . these gathering systems , which originate at the wellhead , reduce the need to transport barrels by truck from the wellhead . as of december 31 , 2015 , we were flowing over 80 % of our gross operated oil production through these gathering systems . please see “ item 1. business—marketing , transportation and major customers . ” our quarterly average net realized oil prices and average price differentials are shown in the tables below . replace_table_token_14_th replace_table_token_15_th replace_table_token_16_th ( 1 ) realized oil prices do not include the effect of derivative contract settlements . ( 2 ) price differential reflects the difference between realized oil prices and wti crude oil index prices . changes in commodity prices may also significantly affect the economic viability of drilling projects as well as the economic valuation and economic recovery of oil and gas reserves . crude oil produced and sold in the williston basin has historically sold at a discount to wti due to transportation costs and takeaway capacity . in the past , there have been periods when this discount has substantially increased due to oil production in the area increasing to a point that it temporarily surpasses the available pipeline transportation , rail transportation and refining capacity in the area . recent expansions of both rail and pipeline facilities have reduced the prior constraint on oil transportation out of the williston basin and improved netback pricing received at the lease . in early 2013 , our average price differentials relative to wti narrowed , primarily due to our ability to access premium coastal markets by rail . as the premium received in coastal markets contracted during the second and third quarters of 2013 , our average price differentials relative to wti increased . in the fourth quarter of 2013 and into the first quarter of 2014 , our average price differentials relative to wti continued to increase due to the pipeline market weakening as a result of refinery down time and increased u.s. and canadian production . in the second and third quarters of 2014 , stronger pipeline prices shifted more of our barrels towards the pipelines , but rail buyers had to compete with pipeline prices despite weaker brent differentials , resulting in price differentials relative to wti of approximately 9 % to 11 % . story_separator_special_tag 52 expenses and other income the following table summarizes our operating expenses , gain on sale of properties and other income and expenses for the periods presented : replace_table_token_18_th ( 1 ) for the year ended december 31 , 2013 , lease operating expenses include midstream income and operating expenses , which are included in well services and midstream revenues and well services and midstream operating expenses , respectively , for the years ended december 31 , 2015 and 2014. year ended december 31 , 2015 as compared to year ended december 31 , 2014 lease operating expenses . lease operating expenses decreased $ 25.1 million to $ 144.5 million for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 . this decrease was primarily due to lower workover costs and an increase in salt water disposal volumes being transported on oms pipelines and injected in oms salt water disposal wells , partially offset by higher costs associated with operating an increased number of producing wells . we completed and placed on production 64.3 total net wells in the williston basin during the year ended december 31 , 2015 as compared to 151.1 total net wells completed and placed on production during the year ended december 31 , 2014 . lease operating expenses decreased from $ 10.18 per boe for the year ended december 31 , 2014 to $ 7.84 per boe for the year ended december 31 , 2015 due to the lower costs and increase in oil and natural gas production . well services and midstream operating expenses . well services and midstream operating expenses represent third-party working interest owners ' share of completion service costs , cost of goods sold and operating expenses incurred by ows and 53 oms . the $ 22.2 million decrease for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 was attributable to a $ 23.8 million decrease in well completion costs as a result of lower well completion product sales to third parties due to ows completing substantially all of opna 's operated wells , coupled with ows completing opna wells with a lower average third-party working interest in the year ended december 31 , 2015 as compared to december 31 , 2014 . this decrease was partially offset by a $ 1.6 million increase related to midstream operating expenses and fresh water purchases . marketing , transportation and gathering expenses . marketing , transportation and gathering expenses increased $ 2.5 million year over year , or a $ 0.03 decrease per boe , which was primarily attributable to a $ 1.4 million increase in gas gathering charges related to additional well connections on oms infrastructure , a $ 1.4 million increase in oil transportation costs associated with having additional wells connected to third-party infrastructure and a $ 0.3 million increase in our pipeline imbalance . these increases were partially offset by a decrease year over year of $ 0.9 million in the write down of our linefill inventory to the lower of cost or market value at year-end . excluding non-cash valuation adjustments , our marketing , transportation and gathering expenses on a per boe basis would have remained constant at $ 1.62 and $ 1.61 for the years ended december 31 , 2015 and 2014 , respectively . the transporting of volumes through third-party oil gathering pipelines increases marketing , transportation and gathering expenses but improves oil price realizations by reducing transportation costs included in our oil price differential for sales at the wellhead . production taxes . our production taxes for the years ended december 31 , 2015 and 2014 were 9.6 % and 9.8 % , respectively , as a percentage of oil and natural gas sales . the production tax rate decreased slightly year over year primarily due to reduced extraction tax rates triggered by lower oil prices on certain north dakota wells , partially offset by an increased weighting of wells in north dakota , which has a higher average production tax rate as compared to montana . for the years ended december 31 , 2015 and 2014 , the percentage of our total production located in north dakota was approximately 88 % and 86 % , respectively . in 2015 and 2014 , north dakota had a crude oil tax structure based on a 5 % production tax and a 6.5 % oil extraction tax , resulting in a combined tax rate of 11.5 % of crude oil revenues . in 2016 , the north dakota oil extraction tax will be reduced to 5 % , resulting in a 10 % combined tax rate , which will rise by 0.5 % if crude oil prices average above $ 90 per barrel for three consecutive months . depreciation , depletion and amortization ( “ dd & a ” ) . dd & a expense increased $ 73.0 million to $ 485.3 million for the year ended december 31 , 2015 as compared to the year ended december 31 , 2014 . the increase in dd & a expense for the year ended december 31 , 2015 was primarily due to an increase in the average dd & a rate per boe year over year coupled with production increases from our wells completed during 2015 . the dd & a rate for the year ended december 31 , 2015 was $ 26.34 per boe as compared to $ 24.74 per boe for the year ended december 31 , 2014 . the increase in the dd & a rate was primarily due to lower recoverable reserves related to lower oil and natural gas prices and increased exploratory and delineation drilling in the three forks formation . rig termination . as a result of our lowered 2015 capital expenditure program , we elected to early terminate certain drilling rig contracts and recorded a rig termination expense of $ 3.9 million for the

