Oil and Gas Reserve Information (Tables)

12 Months Ended

Dec. 31, 2013

Oil and Gas Exploration and Production Industries Disclosures [Abstract]

Schedule of proved developed reserve quantities

The following table sets forth an analysis of the Company’s estimated quantities of net proved and proved developed oil (including condensate), gas and natural gas liquid reserves, all located onshore and offshore the continental United States:

	Oil in MBbls		NGL in MMcfe		Natural Gas in MMcf		Total Reserves in MMcfe
Proved reserves as of December 31, 2010	1,623		8,373		174,566		192,677
Revisions of previous estimates	(294	)	308		8,418		6,962
Extensions, discoveries and other additions	595		8,627		82,113		94,310
Purchase of producing properties	43		91		1,292		1,641
Production	(572	)	(2,288	)	(24,463	)	(30,183	)
Proved reserves as of December 31, 2011	1,395		15,111		241,926		265,407
Revisions of previous estimates	215		(958	)	(52,076	)	(51,744	)
Extensions, discoveries and other additions	647		14,572		46,390		64,844
Sale of reserves in place	(81	)	—		(15,806	)	(16,292	)
Production	(521	)	(3,365	)	(27,466	)	(33,957	)
Proved reserves as of December 31, 2012	1,655		25,360		192,968		228,258
Revisions of previous estimates	(123	)	520		37,738		37,518
Extensions, discoveries and other additions	434		6,099		30,429		39,132
Purchase of producing properties	1,833		1,915		22,274		35,187
Sale of reserves in place	(34	)	—		(15	)	(218	)
Production	(681	)	(4,754	)	(29,226	)	(38,066	)
Proved reserves as of December 31, 2013	3,084		29,140		254,168		301,811
Proved developed reserves
As of December 31, 2011	1,160		11,071		143,441		161,472
As of December 31, 2012	1,225		20,608		140,307		168,265
As of December 31, 2013	2,709		23,173		163,728		203,152
Proved undeveloped reserves
As of December 31, 2011	235		4,040		98,485		103,935
As of December 31, 2012	430		4,752		52,661		59,993
As of December 31, 2013	375		5,967		90,440		98,659

Standardized measure of discounted future cash flows

Standardized Measure

	December 31,
	2013			2012			2011
Future cash flows	$	1,265,663		$	748,914		$	1,080,392
Future production costs	(301,710		)	(220,750		)	(264,219		)
Future development costs	(193,985		)	(121,346		)	(180,846		)
Future income taxes	(40,072		)	(10,205		)	(86,612		)
Future net cash flows	729,896			396,613			548,715
10% annual discount	(276,014		)	(164,218		)	(244,834		)
Standardized measure of discounted future net cash flows	$	453,882		$	232,395		$	303,881

Schedule of changes in standardized measure of discounted future net cash flows

Changes in Standardized Measure

	Year Ended December 31,
	2013			2012			2011
Standardized measure at beginning of year	$	232,395		$	303,881		$	236,375
Sales and transfers of oil and gas produced, net of production costs	(134,184		)	(92,562		)	(116,398		)
Changes in price, net of future production costs	57,293			(138,842		)	(10,219		)
Extensions and discoveries, net of future production and development costs	70,181			104,066			178,901
Changes in estimated future development costs, net of development costs incurred during this period	(24,327		)	69,499			915
Revisions of quantity estimates	57,468			(56,352		)	11,236
Accretion of discount	23,927			34,137			25,565
Net change in income taxes	(14,061		)	30,617			(18,215		)
Purchase of reserves in place	191,964			—			4,805
Sale of reserves in place	(411		)	(8,186		)	—
Changes in production rates (timing) and other	(6,363		)	(13,863		)	(9,084		)
Net increase (decrease) in standardized measure	221,487			(71,486		)	67,506
Standardized measure at end of year	$	453,882		$	232,395		$	303,881

Average sales price and average production costs

The historical twelve-month average prices of oil, gas and natural gas liquids used in determining standardized measure were:

	2013	2012	2011
Oil, $/Bbl	$106.19	$102.81	$101.42
Ngls, $/Mcfe	5.10	6.07	8.62
Natural Gas, $/Mcf	3.11	2.20	3.34