Oil and Natural Gas Operations (Unaudited) (Tables)
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12 Months Ended |
Dec. 31, 2015 |
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| Extractive Industries [Abstract] |
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| Schedule of Capitalized Costs |
The following table sets forth capitalized costs:
| | | | | | | | (in thousands) | December 31, 2015 | December 31, 2014 | Proved | $ | 7,911,554 |
| $ | 8,069,638 |
| Unproved | 150,674 |
| 142,340 |
| Total capitalized costs | 8,062,228 |
| 8,211,978 |
| Accumulated depreciation, depletion and amortization | 3,673,569 |
| 2,663,434 |
| Capitalized costs, net | $ | 4,388,659 |
| $ | 5,548,544 |
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| Schedule of Cost Incurred in Property Acquisition, Exploration and Development Activities |
The following table sets forth costs incurred in property acquisition, exploration and development activities and includes both capitalized costs and costs charged to expense during the year:
| | | | | | | | | | | Years ended December 31, (in thousands) | 2015 | 2014 | 2013 | Property acquisition: | | | | Proved | $ | 1,866 |
| $ | 2,582 |
| $ | 4,661 |
| Unproved | 85,690 |
| 68,514 |
| 26,820 |
| Exploration | 649,764 |
| 972,164 |
| 435,636 |
| Development | 372,177 |
| 408,949 |
| 655,353 |
| Total costs incurred | $ | 1,109,497 |
| $ | 1,452,209 |
| $ | 1,122,470 |
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| Schedule of Results of Operations from Producing Activities |
The following table sets forth results of Energen’s oil, natural gas liquids and natural gas operations from producing activities:
| | | | | | | | | | | Years ended December 31, (in thousands) | 2015 | 2014 | 2013 | Gross revenues* | $ | 878,554 |
| $ | 1,679,213 |
| $ | 1,206,293 |
| Production (lifting costs) | 285,760 |
| 376,495 |
| 351,541 |
| Exploration expense | 14,877 |
| 28,090 |
| 14,036 |
| Depreciation, depletion and amortization including asset impairments | 1,880,190 |
| 960,539 |
| 463,606 |
| Accretion expense | 7,108 |
| 7,608 |
| 6,995 |
| Income tax expense (benefit) | (469,362 | ) | 99,469 |
| 128,773 |
| Results of operations from producing activities | $ | (840,019 | ) | $ | 207,012 |
| $ | 241,342 |
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* The years ended December 31, 2015, 2014 and 2013 gross revenues include a pre-tax non-cash mark-to-market loss on derivatives of $281.8 million, a pre-tax non-cash mark-to-market gain on derivatives of $315.4 million and a pre-tax non-cash mark-to-market loss on derivatives of $47.8 million, respectively. |
| Schedule of Proved Developed and Undeveloped Oil and Gas Reserves |
The independent reservoir engineers have issued reports covering approximately 99 percent of Energen’s ending proved reserves indicating that in their judgment the estimates are reasonable in the aggregate.
| | | | | | | | | | Year ended December 31, 2015 | Oil MBbl | NGL MBbl | Natural Gas MMcf | Total MMBOE | Proved reserves at beginning of period | 181,227 |
| 73,463 |
| 707,926 |
| 372.7 |
| Revisions of previous estimates | (39,537 | ) | (11,979 | ) | (44,176 | ) | (58.9 | ) | Purchases | 2 |
| 1 |
| 2 |
| — |
| Extensions and discoveries | 83,319 |
| 25,530 |
| 143,022 |
| 132.6 |
| Production | (14,023 | ) | (4,065 | ) | (35,604 | ) | (24.0 | ) | Sales | (297 | ) | (11,237 | ) | (337,266 | ) | (67.7 | ) | Proved reserves at end of period | 210,691 |
| 71,713 |
| 433,904 |
| 354.7 |
| Proved developed reserves at end of period | 108,319 |
| 36,374 |
| 236,112 |
| 184.0 |
| Proved undeveloped reserves at end of period | 102,372 |
| 35,339 |
| 197,792 |
| 170.7 |
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| | | | | | | | | | Year ended December 31, 2014 | Oil MBbl | NGL MBbl | Natural Gas MMcf | Total MMBOE | Proved reserves at beginning of period | 164,870 |
| 63,011 |
| 719,725 |
| 347.8 |
| Revisions of previous estimates | (48,548 | ) | (15,165 | ) | (71,806 | ) | (75.7 | ) | Purchases | 88 |
| 26 |
| 116 |
| 0.1 |
| Extensions and discoveries | 76,722 |
| 29,695 |
| 141,209 |
| 130 |
| Production | (11,818 | ) | (4,104 | ) | (59,562 | ) | (25.8 | ) | Sales | (87 | ) | — |
| (21,756 | ) | (3.7 | ) | Proved reserves at end of period | 181,227 |
| 73,463 |
| 707,926 |
| 372.7 |
| Proved developed reserves at end of period | 118,697 |
| 47,621 |
| 589,074 |
| 264.5 |
| Proved undeveloped reserves at end of period | 62,530 |
| 25,842 |
| 118,852 |
| 108.2 |
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| | | | | | | | | | Year ended December 31, 2013 | Oil MBbl | NGL MBbl | Natural Gas MMcf | Total MMBOE | Proved reserves at beginning of period | 155,348 |
| 56,155 |
| 809,128 |
| 346.4 |
| Revisions of previous estimates | (680 | ) | 2,211 |
| 18,465 |
| 4.6 |
| Purchases | 142 |
| 56 |
| 282 |
| 0.2 |
| Extensions and discoveries | 20,517 |
| 7,823 |
| 50,568 |
| 36.8 |
| Production | (10,378 | ) | (3,233 | ) | (70,506 | ) | (25.4 | ) | Sales | (79 | ) | (1 | ) | (88,212 | ) | (14.8 | ) | Proved reserves at end of period | 164,870 |
| 63,011 |
| 719,725 |
| 347.8 |
| Proved developed reserves at end of period | 113,795 |
| 42,087 |
| 623,305 |
| 259.8 |
| Proved undeveloped reserves at end of period | 51,075 |
| 20,924 |
| 96,420 |
| 88.0 |
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| Schedule of Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves |
| | | | | | | | | | | Years ended December 31, (in thousands) | 2015 | 2014 | 2013 | Future gross revenues | $ | 11,714,729 |
| $ | 20,971,672 |
| $ | 19,509,305 |
| Future production costs | 4,353,974 |
| 7,532,273 |
| 6,136,709 |
| Future development costs | 1,961,661 |
| 1,784,738 |
| 1,896,602 |
| Future income tax expense | 1,065,887 |
| 3,440,582 |
| 3,209,697 |
| Future net cash flows | 4,333,207 |
| 8,214,079 |
| 8,266,297 |
| Discount at 10% per annum | 2,299,859 |
| 3,994,423 |
| 4,248,456 |
| Standardized measure of discounted future net cash flows relating to proved oil and natural gas reserves | $ | 2,033,348 |
| $ | 4,219,656 |
| $ | 4,017,841 |
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| Schedule of Principal Sources of Changes in Standardized Measure of Discounted Future Net Cash Flows |
The following are the principal sources of changes in the standardized measure of discounted future net cash flows:
| | | | | | | | | | | Years ended December 31, (in thousands) | 2015 | 2014 | 2013 | Balance at beginning of year | $ | 4,219,656 |
| $ | 4,017,841 |
| $ | 3,699,319 |
| Revisions to reserves proved in prior years: | | | | Net changes in prices, production costs and future development costs | (2,861,591 | ) | (1,147,028 | ) | 566,838 |
| Net changes due to revisions in quantity estimates | (404,708 | ) | (1,285,394 | ) | (81,762 | ) | Development costs incurred, previously estimated | 350,560 |
| 337,198 |
| 299,432 |
| Accretion of discount | 421,966 |
| 401,784 |
| 369,932 |
| Changes in timing and other* | (903,975 | ) | 987,652 |
| (179,502 | ) | Total revisions | (3,397,748 | ) | (705,788 | ) | 974,938 |
| New field discoveries and extensions, net of future production and development costs | 776,315 |
| 2,321,028 |
| 376,326 |
| Sales of oil and gas produced, net of production costs | (514,380 | ) | (1,054,553 | ) | (1,014,593 | ) | Purchases | 8 |
| 4,241 |
| 4,690 |
| Sales | (372,039 | ) | (21,092 | ) | (24,876 | ) | Net change in income taxes | 1,321,536 |
| (342,021 | ) | 2,037 |
| Net change in standardized measure of discounted future net cash flows | (2,186,308 | ) | 201,815 |
| 318,522 |
| Balance at end of year | $ | 2,033,348 |
| $ | 4,219,656 |
| $ | 4,017,841 |
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*Amount represents changes in production timing and other. In 2015, the production timing is significantly affected by changes related to the delay of the drilling program. For 2014, the production timing is significantly affected by changes related to the acceleration of the horizontal drilling program and the delay of the vertical drilling program.
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