see `` risk factors— commodity prices fluctuate widely , and low prices for an extended period would likely have a material adverse impact on our business `` and `` risk factors— our future performance depends on our ability to find or acquire additional natural gas and oil reserves that are economically recoverable `` in item 1a . 38 we account for our derivative instruments on a mark-to-market basis with changes in fair value recognized in operating revenues in the consolidated statement of operations . as a result of these mark-to-market adjustments associated with our derivative instruments , we will experience volatility in our earnings due to commodity price volatility . refer to “ impact of derivative instruments on operating revenues ” below and note 6 of the notes to the consolidated financial statements for more information . commodity prices have been and are expected to remain volatile . we believe that we are well-positioned to manage the challenges presented in a volatile commodity pricing environment by : continuing to exercise discipline in our capital program with the expectation of funding our capital expenditures with operating cash flows , and if required , borrowings under our revolving credit facility . continuing to optimize our drilling , completion and operational efficiencies , resulting in lower operating costs per unit of production . continuing to manage our balance sheet , which we believe provides sufficient availability under our revolving credit facility and existing cash balances to meet our capital requirements and maintain compliance with our debt covenants . continuing to manage price risk by strategically hedging our production . while we are unable to predict future commodity prices , in the e vent that commodity prices significantly decline , management would test the recoverability of the carrying value of its oil and gas properties and , if necessary , record an impairment charge . financial condition capital resources and liquidity our primary sources of cash in 2018 were from the sale of natural gas and crude oil production and proceeds from the sale of assets . these cash flows were primarily used to fund our capital expenditures , contributions to our equity method investments , principal and interest payments on debt , repurchase of shares of our common stock and payment of dividends . see below for additional discussion and analysis of cash flow . the borrowing base under the terms of our revolving credit facility is redetermined annually in april . in addition , either we or the banks may request an interim redetermination twice a year or in connection with certain acquisitions or divestitures of oil and gas properties . effective april 18 , 2018 , the borrowing base and available commitments were reaffirmed at $ 3.2 billion and $ 1.7 billion , respectively . as of december 31 , 2018 , we had $ 7.0 million of borrowings outstanding and unused commitments of $ 1.8 billion under our revolving credit facility . a decline in commodity prices could result in the future reduction of our borrowing base and related commitments under our revolving credit facility . unless commodity prices decline significantly from current levels , we do not believe that any such reductions would have a significant impact on our ability to service our debt and fund our drilling program and related operations . we strive to manage our debt at a level below the available credit line in order to maintain borrowing capacity . our revolving credit facility includes a covenant limiting our total debt . we believe that , with internally generated cash flow and availability under our revolving credit facility , we have the capacity to finance our spending plans . at december 31 , 2018 , we were in compliance with all restrictive financial covenants for both our revolving credit facility and senior notes . see note 5 of the notes to the consolidated financial statements for further details regarding our debt . 39 cash flows our cash flows from operating activities , investing activities and financing activities are as follows : replace_table_token_14_th operating activities . operating cash flow fluctuations are substantially driven by commodity prices , changes in our production volumes and operating expenses . commodity prices have historically been volatile , primarily as a result of supply and demand for natural gas and crude oil , pipeline infrastructure constraints , basis differentials , inventory storage levels and seasonal influences . in addition , fluctuations in cash flow may result in an increase or decrease in our capital expenditures . see `` results of operations `` for a review of the impact of prices and volumes on revenues . our working capital is substantially influenced by the variables discussed above and fluctuates based on the timing and amount of borrowings and repayments under our revolving credit facility , repayments of debt , the timing of cash collections and payments on our trade accounts receivable and payable , respectively , repurchases of our securities and changes in the fair value of our commodity derivative activity . from time to time , our working capital will reflect a deficit , while at other times it will reflect a surplus . this fluctuation is not unusual . at december 31 , 2018 and 2017 , we had a working capital surplus of $ 257.3 million and $ 134.9 million , respectively . we believe we have adequate liquidity and availability under our revolving credit facility available to meet our working capital requirements over the next twelve months . net cash provided by operating activities in 2018 increase d by $ 206.7 million compared to 2017 . this increase was primarily due to higher operating revenues , partially offset by higher operating expenses ( excluding non-cash expenses ) and unfavorable changes in working capital and other assets and liabilities . the increase in operating revenues was primarily due to an increase in realized natural gas and crude oil prices and higher equivalent production . story_separator_special_tag generally , if the related commodity index declines , the price that we receive for our production will also decline . therefore , the amount of revenue that we realize is determined by certain factors that are beyond our control . however , management may mitigate this price risk on a portion of our anticipated production with the use of financial commodity derivatives , including collars and swaps to reduce the impact of sustained lower pricing on our revenue . under both arrangements , there is also a risk that the movement of index prices may result in our inability to realize the full benefit of an improvement in market conditions . results of operations 2018 and 2017 compared we reported net income for 2018 of $ 557.0 million , or $ 1.25 per share , compared to net income for 2017 of $ 100.4 million , or $ 0.22 per share . the increase in net income was primarily due to higher operating revenues , lower operating expenses and higher earnings on equity method investments , partially offset by higher income tax expense . 45 revenue , price and volume variances our revenues vary from year to year as a result of changes in commodity prices and production volumes . below is a discussion of revenue , price and volume variances . replace_table_token_18_th replace_table_token_19_th natural gas revenues the increase in natural gas revenues of $ 375.1 million was due to higher natural gas prices and production . the increase in production was a result of an increase in our drilling and completion activities in the marcellus shale . crude oil and condensate revenues the decrease in crude oil and condensate revenues of $ 163.6 million was due to lower production , partially offset by higher crude oil prices . the decrease in production was the result of the sale of our eagle ford shale assets in february 2018. impact of derivative instruments on operating revenues replace_table_token_20_th brokered natural gas replace_table_token_21_th 46 the $ 23.4 million increase in brokered natural gas margin is a result of an increase in brokered activity . this increase was due to higher volumes associated with natural gas purchases that were required to satisfy certain sales obligations . operating and other expenses replace_table_token_22_th total costs and expenses from operations decrease d by $ 402.3 million from 2017 to 2018 . the primary reasons for this fluctuation are as follows : direct operations decrease d $ 32.7 million largely due to the sale of our oil and gas properties in west virginia in the third quarter of 2017 and the eagle ford shale assets in the first quarter of 2018 , partially offset by an increase in operating costs primarily driven by higher marcellus shale production . transportation and gathering increase d $ 15.3 million due to higher throughput as a result of higher marcellus shale production , partially offset by a decrease in transportation and gathering related to the sale of our eagle ford shale assets in the first quarter of 2018. brokered natural gas increase d $ 168.9 million from 2017 to 2018 . see the preceding table titled `` brokered natural gas `` for further analysis . taxes other than income decrease d $ 10.8 million due to $ 9.3 million lower production taxes and $ 5.5 million lower ad valorem taxes resulting from the sale of our oil and gas properties in west virginia in the third quarter of 2017 and the eagle ford shale assets in the first quarter of 2018. these decrease s were partially offset by $ 4.7 million higher drilling impact fees due to an increase in rates associated with higher natural gas prices . exploration increase d $ 92.3 million as a result of an increase in exploratory dry hole expense of $ 93.9 million . the exploratory dry hole costs in 2018 relate to our activities in west texas and ohio . these increases were partially offset by a decrease of $ 2.7 million in geological and geophysical costs associated with our exploration activities . depreciation , depletion and amortization decrease d $ 151.3 million primarily due to lower dd & a of $ 175.6 million and lower accretion of asset retirement obligations of $ 2.7 million , partially offset by higher amortization of undeveloped leases of $ 29.6 million . the decrease in dd & a was primarily due to a decrease of $ 212.1 million related to a lower dd & a rate of $ 0.45 per mcfe for 2018 compared to $ 0.73 per mcfe for 2017 , partially offset by an increase of $ 36.5 million due to higher equivalent production volumes in the marcellus shale . the lower dd & a rate was primarily due to lower cost reserve additions and sales of higher dd & a rate fields . amortization of undeveloped leasehold costs increased due to higher amortization associated with our exploration areas . 47 impairment of oil and gas properties was $ 482.8 million in 2017 due to a $ 414.3 million impairment of oil and gas properties located in south texas and $ 68.6 million impairment of oil and gas properties and related pipeline assets in west virginia , virginia and ohio . there were no impairments of oil and gas properties in 2018. general and administrative decrease d $ 1.1 million . there were no changes in general and administrative expenses that were individually significant . earnings ( loss ) on equity method investments the increase in earnings ( loss ) on equity method investments is due to an other than temporary impairment of $ 95.9 million associated with our equity method investment in constitution that was recognized in 2017 , partially offset by the recognition of our proportionate share of net earnings from our equity method investment in meade , which commenced operations in late 2018 . loss on sale of assets during 2018 , we recognized a net aggregate loss of $ 16.3 million

cash flows used in investing activities decrease d by $ 412.8 million from 2017 to 2018 due to $ 562.9 million higher proceeds from the sale of assets primarily due to the divestiture of our eagle ford shale assets in february 2018 and our haynesville shale assets in july 2018. this change was partially offset by $ 129.9 million higher capital expenditures and $ 20.2 million higher capital contributions associated with our equity method investments . cash flows used in investing activities increased by $ 352.9 million from 2016 to 2017 due to an increase of $ 389.4 million in capital expenditures and $ 28.6 million higher capital contributions associated with our equity method investments , partially offset by $ 65.0 million higher proceeds from the sale of assets . financing activities . cash flows used in financing activities increase d by $ 1,078.8 million from 2017 to 2018 due to $ 749.0 million higher repurchases of our common stock in 2018 , $ 297.0 million of higher net repayments of debt primarily related to maturities of certain of our senior notes during 2018 and $ 32.5 million of higher dividend payments related to an increase in our dividend rate in 2018. cash flows provided by financing activities decreased by $ 664.3 million from 2016 to 2017 due to $ 995.3 million lower net proceeds from the issuance of common stock in 2016 , $ 123.7 million of repurchases of our common stock in 2017 and $ 42.7 million of higher dividend payments related to an increase in the dividend rate in 2017 and the issuance of common stock 40 in 2016. these decreases were partially offset by $ 497.0 million of lower net repayments of debt due to the repayment of the outstanding balance on our revolving credit facility and certain of our senior notes with the proceeds from the issuance of common stock in 2016. capitalization information about our capitalization is as follows : replace_table_token_15_th _ ( 1 ) includes $ 7.0 million of borrowings outstanding under our revolving credit


 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.
     ```cash flows used in investing activities decrease d by $ 412.8 million from 2017 to 2018 due to $ 562.9 million higher proceeds from the sale of assets primarily due to the divestiture of our eagle ford shale assets in february 2018 and our haynesville shale assets in july 2018. this change was partially offset by $ 129.9 million higher capital expenditures and $ 20.2 million higher capital contributions associated with our equity method investments . cash flows used in investing activities increased by $ 352.9 million from 2016 to 2017 due to an increase of $ 389.4 million in capital expenditures and $ 28.6 million higher capital contributions associated with our equity method investments , partially offset by $ 65.0 million higher proceeds from the sale of assets . financing activities . cash flows used in financing activities increase d by $ 1,078.8 million from 2017 to 2018 due to $ 749.0 million higher repurchases of our common stock in 2018 , $ 297.0 million of higher net repayments of debt primarily related to maturities of certain of our senior notes during 2018 and $ 32.5 million of higher dividend payments related to an increase in our dividend rate in 2018. cash flows provided by financing activities decreased by $ 664.3 million from 2016 to 2017 due to $ 995.3 million lower net proceeds from the issuance of common stock in 2016 , $ 123.7 million of repurchases of our common stock in 2017 and $ 42.7 million of higher dividend payments related to an increase in the dividend rate in 2017 and the issuance of common stock 40 in 2016. these decreases were partially offset by $ 497.0 million of lower net repayments of debt due to the repayment of the outstanding balance on our revolving credit facility and certain of our senior notes with the proceeds from the issuance of common stock in 2016. capitalization information about our capitalization is as follows : replace_table_token_15_th _ ( 1 ) includes $ 7.0 million of borrowings outstanding under our revolving credit
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 Suspicious Activity Report : see `` risk factors— commodity prices fluctuate widely , and low prices for an extended period would likely have a material adverse impact on our business `` and `` risk factors— our future performance depends on our ability to find or acquire additional natural gas and oil reserves that are economically recoverable `` in item 1a . 38 we account for our derivative instruments on a mark-to-market basis with changes in fair value recognized in operating revenues in the consolidated statement of operations . as a result of these mark-to-market adjustments associated with our derivative instruments , we will experience volatility in our earnings due to commodity price volatility . refer to “ impact of derivative instruments on operating revenues ” below and note 6 of the notes to the consolidated financial statements for more information . commodity prices have been and are expected to remain volatile . we believe that we are well-positioned to manage the challenges presented in a volatile commodity pricing environment by : continuing to exercise discipline in our capital program with the expectation of funding our capital expenditures with operating cash flows , and if required , borrowings under our revolving credit facility . continuing to optimize our drilling , completion and operational efficiencies , resulting in lower operating costs per unit of production . continuing to manage our balance sheet , which we believe provides sufficient availability under our revolving credit facility and existing cash balances to meet our capital requirements and maintain compliance with our debt covenants . continuing to manage price risk by strategically hedging our production . while we are unable to predict future commodity prices , in the e vent that commodity prices significantly decline , management would test the recoverability of the carrying value of its oil and gas properties and , if necessary , record an impairment charge . financial condition capital resources and liquidity our primary sources of cash in 2018 were from the sale of natural gas and crude oil production and proceeds from the sale of assets . these cash flows were primarily used to fund our capital expenditures , contributions to our equity method investments , principal and interest payments on debt , repurchase of shares of our common stock and payment of dividends . see below for additional discussion and analysis of cash flow . the borrowing base under the terms of our revolving credit facility is redetermined annually in april . in addition , either we or the banks may request an interim redetermination twice a year or in connection with certain acquisitions or divestitures of oil and gas properties . effective april 18 , 2018 , the borrowing base and available commitments were reaffirmed at $ 3.2 billion and $ 1.7 billion , respectively . as of december 31 , 2018 , we had $ 7.0 million of borrowings outstanding and unused commitments of $ 1.8 billion under our revolving credit facility . a decline in commodity prices could result in the future reduction of our borrowing base and related commitments under our revolving credit facility . unless commodity prices decline significantly from current levels , we do not believe that any such reductions would have a significant impact on our ability to service our debt and fund our drilling program and related operations . we strive to manage our debt at a level below the available credit line in order to maintain borrowing capacity . our revolving credit facility includes a covenant limiting our total debt . we believe that , with internally generated cash flow and availability under our revolving credit facility , we have the capacity to finance our spending plans . at december 31 , 2018 , we were in compliance with all restrictive financial covenants for both our revolving credit facility and senior notes . see note 5 of the notes to the consolidated financial statements for further details regarding our debt . 39 cash flows our cash flows from operating activities , investing activities and financing activities are as follows : replace_table_token_14_th operating activities . operating cash flow fluctuations are substantially driven by commodity prices , changes in our production volumes and operating expenses . commodity prices have historically been volatile , primarily as a result of supply and demand for natural gas and crude oil , pipeline infrastructure constraints , basis differentials , inventory storage levels and seasonal influences . in addition , fluctuations in cash flow may result in an increase or decrease in our capital expenditures . see `` results of operations `` for a review of the impact of prices and volumes on revenues . our working capital is substantially influenced by the variables discussed above and fluctuates based on the timing and amount of borrowings and repayments under our revolving credit facility , repayments of debt , the timing of cash collections and payments on our trade accounts receivable and payable , respectively , repurchases of our securities and changes in the fair value of our commodity derivative activity . from time to time , our working capital will reflect a deficit , while at other times it will reflect a surplus . this fluctuation is not unusual . at december 31 , 2018 and 2017 , we had a working capital surplus of $ 257.3 million and $ 134.9 million , respectively . we believe we have adequate liquidity and availability under our revolving credit facility available to meet our working capital requirements over the next twelve months . net cash provided by operating activities in 2018 increase d by $ 206.7 million compared to 2017 . this increase was primarily due to higher operating revenues , partially offset by higher operating expenses ( excluding non-cash expenses ) and unfavorable changes in working capital and other assets and liabilities . the increase in operating revenues was primarily due to an increase in realized natural gas and crude oil prices and higher equivalent production . story_separator_special_tag generally , if the related commodity index declines , the price that we receive for our production will also decline . therefore , the amount of revenue that we realize is determined by certain factors that are beyond our control . however , management may mitigate this price risk on a portion of our anticipated production with the use of financial commodity derivatives , including collars and swaps to reduce the impact of sustained lower pricing on our revenue . under both arrangements , there is also a risk that the movement of index prices may result in our inability to realize the full benefit of an improvement in market conditions . results of operations 2018 and 2017 compared we reported net income for 2018 of $ 557.0 million , or $ 1.25 per share , compared to net income for 2017 of $ 100.4 million , or $ 0.22 per share . the increase in net income was primarily due to higher operating revenues , lower operating expenses and higher earnings on equity method investments , partially offset by higher income tax expense . 45 revenue , price and volume variances our revenues vary from year to year as a result of changes in commodity prices and production volumes . below is a discussion of revenue , price and volume variances . replace_table_token_18_th replace_table_token_19_th natural gas revenues the increase in natural gas revenues of $ 375.1 million was due to higher natural gas prices and production . the increase in production was a result of an increase in our drilling and completion activities in the marcellus shale . crude oil and condensate revenues the decrease in crude oil and condensate revenues of $ 163.6 million was due to lower production , partially offset by higher crude oil prices . the decrease in production was the result of the sale of our eagle ford shale assets in february 2018. impact of derivative instruments on operating revenues replace_table_token_20_th brokered natural gas replace_table_token_21_th 46 the $ 23.4 million increase in brokered natural gas margin is a result of an increase in brokered activity . this increase was due to higher volumes associated with natural gas purchases that were required to satisfy certain sales obligations . operating and other expenses replace_table_token_22_th total costs and expenses from operations decrease d by $ 402.3 million from 2017 to 2018 . the primary reasons for this fluctuation are as follows : direct operations decrease d $ 32.7 million largely due to the sale of our oil and gas properties in west virginia in the third quarter of 2017 and the eagle ford shale assets in the first quarter of 2018 , partially offset by an increase in operating costs primarily driven by higher marcellus shale production . transportation and gathering increase d $ 15.3 million due to higher throughput as a result of higher marcellus shale production , partially offset by a decrease in transportation and gathering related to the sale of our eagle ford shale assets in the first quarter of 2018. brokered natural gas increase d $ 168.9 million from 2017 to 2018 . see the preceding table titled `` brokered natural gas `` for further analysis . taxes other than income decrease d $ 10.8 million due to $ 9.3 million lower production taxes and $ 5.5 million lower ad valorem taxes resulting from the sale of our oil and gas properties in west virginia in the third quarter of 2017 and the eagle ford shale assets in the first quarter of 2018. these decrease s were partially offset by $ 4.7 million higher drilling impact fees due to an increase in rates associated with higher natural gas prices . exploration increase d $ 92.3 million as a result of an increase in exploratory dry hole expense of $ 93.9 million . the exploratory dry hole costs in 2018 relate to our activities in west texas and ohio . these increases were partially offset by a decrease of $ 2.7 million in geological and geophysical costs associated with our exploration activities . depreciation , depletion and amortization decrease d $ 151.3 million primarily due to lower dd & a of $ 175.6 million and lower accretion of asset retirement obligations of $ 2.7 million , partially offset by higher amortization of undeveloped leases of $ 29.6 million . the decrease in dd & a was primarily due to a decrease of $ 212.1 million related to a lower dd & a rate of $ 0.45 per mcfe for 2018 compared to $ 0.73 per mcfe for 2017 , partially offset by an increase of $ 36.5 million due to higher equivalent production volumes in the marcellus shale . the lower dd & a rate was primarily due to lower cost reserve additions and sales of higher dd & a rate fields . amortization of undeveloped leasehold costs increased due to higher amortization associated with our exploration areas . 47 impairment of oil and gas properties was $ 482.8 million in 2017 due to a $ 414.3 million impairment of oil and gas properties located in south texas and $ 68.6 million impairment of oil and gas properties and related pipeline assets in west virginia , virginia and ohio . there were no impairments of oil and gas properties in 2018. general and administrative decrease d $ 1.1 million . there were no changes in general and administrative expenses that were individually significant . earnings ( loss ) on equity method investments the increase in earnings ( loss ) on equity method investments is due to an other than temporary impairment of $ 95.9 million associated with our equity method investment in constitution that was recognized in 2017 , partially offset by the recognition of our proportionate share of net earnings from our equity method investment in meade , which commenced operations in late 2018 . loss on sale of assets during 2018 , we recognized a net aggregate loss of $ 16.3 million

