Disclosures About Oil and Gas Producing Activities (unaudited) | 10. Disclosures About Oil and Gas Producing Activities (unaudited) Proved Reserves All of our estimated oil and natural gas reserves are attributable to properties within the United States, primarily in the Permian Basin in West Texas. The estimates of proved reserves and related valuations for the years ended December 31, 2016, 2015 and 2014, were prepared by DeGolyer and MacNaughton, independent petroleum engineers. Each year’s estimate of proved reserves and related valuations were also prepared in accordance with then-current rules and guidelines established by the Securities and Exchange Commission and the Financial Accounting Standards Board. The following table summarizes the prices used in the reserve estimates for 2016, 2015 and 2014. Commodity prices used for the reserve estimates, adjusted for basis differentials, grade and quality, are as follows: 2016 2015 2014 Oil (per Bbl) $ 42.69 $ 50.16 $ 94.56 Natural gas liquids (per Bbl) $ 14.12 $ 15.13 $ 31.50 Gas (per Mcf) $ 2.47 $ 2.64 $ 4.55 Oil, NGLs and natural gas reserve estimates are subject to numerous uncertainties inherent in the estimation of quantities of proved reserves and in the projection of future rates of production and the timing of development expenditures. The accuracy of such estimates is a function of the quality of available data and of engineering and geological interpretation and judgment. Results of subsequent drilling, testing and production may cause either upward or downward revision of previous estimates. Further, the volumes considered to be commercially recoverable fluctuate with changes in prices and operating costs. The Company emphasizes that reserve estimates are inherently imprecise and that estimates of new discoveries are more imprecise than those of currently producing oil and natural gas properties. Accordingly, these estimates are expected to change as additional information becomes available in the future. The following table provides a summary of the changes of the total proved reserves for the years ended December 31, 2016, 2015 and 2014, as well as proved developed and proved undeveloped reserves at the beginning and end of each respective year. Total Proved Reserves Oil (MBbls) NGLs (MBbls) Natural Gas (MMcf) Total (MBoe) Balance — January 1, 2014 46,067 32,593 216,002 114,661 Extensions and discoveries 19,347 10,658 79,454 43,247 Production(1) (2,024 ) (1,461 ) (10,773 ) (5,281 ) Revisions to previous estimates (8,052 ) (883 ) 15,337 (6,379 ) Balance — December 31, 2014 55,338 40,907 300,020 146,248 Extensions and discoveries 11,054 10,630 79,268 34,895 Production(1) (1,882 ) (1,694 ) (13,262 ) (5,787 ) Revisions to previous estimates (10,014 ) (357 ) 9,962 (8,710 ) Balance — December 31, 2015 54,496 49,486 375,988 166,646 Extensions and discoveries 6,529 4,564 33,347 16,651 Production(1) (1,275 ) (1,529 ) (11,734 ) (4,759 ) Revisions to previous estimates (9,719 ) (4,887 ) (45,324 ) (22,161 ) Balance — December 31, 2016 50,031 47,634 352,277 156,377 (1) Production included 1,390 MMcf, 1,530 MMcf and 1,330 MMcf related to field fuel in 2014, 2015 and 2016, respectively. Total Proved Reserves Oil (MBbls) NGLs (MBbls) Natural Gas (MMcf) Total (MBoe) Proved Developed Reserves: January 1, 2014 13,646 14,919 99,742 45,189 December 31, 2014 17,978 19,082 138,961 60,220 December 31, 2015 15,667 20,414 154,652 61,856 December 31, 2016 13,466 20,375 150,208 58,875 Proved Undeveloped Reserves: January 1, 2014 32,421 17,674 116,260 69,472 December 31, 2014 37,360 21,825 161,059 86,028 December 31, 2015 38,829 29,072 221,335 104,790 December 31, 2016 36,565 27,259 202,069 97,502 The following is a discussion of the material changes in our proved reserve quantities for the years ended December 31, 2016, 2015 and 2014: Year Ended December 31, 2016 Extensions and discoveries for 2016 were 16.7 MMBoe, primarily attributable to our development project in the Wolfcamp shale oil resource play in the Permian Basin. During 2016, we reclassified 22.4 MMBoe of proved undeveloped reserves to unproved reserves. The reserves reclassified are attributable to horizontal well locations in Project Pangea that are no longer expected to be developed within five years from their initial booking, as required by SEC rules. Revisions included an increase of 2.1 MMBoe resulting from cost reductions, updated well performance and technical parameters, offset by a decrease of 1.9 MMBoe due to lower commodity prices. We produced 4.8 MMBoe during 2016. This production included 1,330 MMcf of gas that was produced and used as field fuel (primarily for compressors and artificial lift) before the gas was delivered to a sales point. Year Ended December 31, 2015 Extensions and discoveries for 2015 were 34.9 MMBoe, primarily attributable to our development project in the Wolfcamp shale oil resource play in the Permian Basin. During 2015, we reclassified 11.9 MMBoe of proved reserves to unproved reserves. The reserves reclassified are attributable to horizontal and vertical well locations in Project Pangea that are no longer expected to be developed within five years from their initial booking, as required by SEC rules. Revisions included an increase of 13 MMBoe resulting from cost reductions, updated well performance and technical parameters, offset by a decrease of 9.8 MMBoe due to lower commodity prices. We produced 5.8 MMBoe during 2015. This production included 1,530 MMcf of gas that was produced and used as field fuel (primarily for compressors and artificial lift) before the gas was delivered to a sales point. Year Ended December 31, 2014 Extensions and discoveries for 2014 were 43.2 MMBoe, primarily attributable to our development project in the Wolfcamp shale oil resource play in the Permian Basin. During 2014, we reclassified 9.3 MMBoe of proved undeveloped reserves to unproved reserves. The reserves reclassified included 5.8 MMBoe attributable to vertical Canyon locations in Project Pangea that we do not plan to drill within five years from their initial booking, and 3.5 MMBoe attributable to horizontal Wolfcamp locations that are no longer included in our proved development plan. Revisions included an increase of 6.3 MMBoe attributable to updated well performance and an increase of 0.7 MMBoe due to pricing, offset by a decrease of 4.1 MMBoe resulting from updated technical parameters and costs. We produced 5.3 MMBoe during 2014. This production included 1,390 MMcf of gas that was produced and used as field fuel (primarily for compressors and artificial lift) before the gas was delivered to a sales point. Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Reserves The standardized measure of discounted future net cash flows is computed by applying the 12-month unweighted average of the first-day-of-the-month pricing for oil and natural gas (with consideration of price changes only to the extent provided by contractual arrangements) to the estimated future production of proved oil and natural gas reserves less estimated future expenditures (based on year-end costs) to be incurred in developing and producing the proved reserves, discounted using a rate of 10 percent per year to reflect the estimated timing of the future cash flows. Future income taxes are calculated by comparing undiscounted future cash flows to the tax basis of oil and natural gas properties plus available carryforwards and credits and applying the current tax rates to the difference. Discounted future cash flow estimates like those shown below are not intended to represent estimates of the fair value of oil and natural gas properties. Estimates of fair value would also consider probable and possible reserves, anticipated future oil and natural gas prices, interest rates, changes in development and production costs and risks associated with future production. Because of these and other considerations, any estimate of fair value is necessarily subjective and imprecise. The following table provides the standardized measure of discounted future net cash flows at December 31, 2016, 2015 and 2014 (in thousands): Years Ended December 31, 2016 2015 2014 Future cash flows $ 3,319,551 $ 4,097,568 $ 7,430,368 Future production costs (1,054,211 ) (1,237,888 ) (1,704,333 ) Future development costs (829,926 ) (934,814 ) (1,247,446 ) Future income tax expense (132,834 ) (307,374 ) (1,267,025 ) Future net cash flows 1,302,580 1,617,492 3,211,564 10% annual discount for estimated timing of cash flows (1,004,825 ) (1,157,097 ) (2,155,749 ) Standardized measure of discounted future net cash flows $ 297,755 $ 460,395 $ 1,055,815 Future cash flows as shown above were reported without consideration for the effects of commodity derivative transactions outstanding at each period end. Changes in Standardized Measure of Discounted Future Net Cash Flows The changes in the standardized measure of discounted future net cash flows relating to proved oil and natural gas reserves are as follows (in thousands): Years Ended December 31, 2016 2015 2014 Balance, beginning of period $ 460,395 $ 1,055,815 $ 676,277 Net change in sales and transfer prices and in production (lifting) costs related to future production (191,841 ) (1,405,864 ) (59,920 ) Changes in estimated future development costs 17,405 231,900 (388,772 ) Sales and transfers of oil and gas produced during the period (62,835 ) (91,278 ) (209,893 ) Net change due to extensions, discoveries and improved recovery 13,988 156,783 534,231 Net change due to revisions in quantity estimates (25,236 ) (59,305 ) (78,801 ) Previously estimated development costs incurred during the period 15,884 146,237 382,995 Accretion of discount 46,040 105,582 113,188 Other (9,500 ) 6,915 (11,897 ) Net change in income taxes 33,455 313,610 98,407 Standardized Measure of discounted future net cash flows $ 297,755 $ 460,395 $ 1,055,815 |