Asset Retirement Obligations

12 Months Ended

Dec. 31, 2013

(9)	ASSET RETIREMENT OBLIGATIONS

Our asset retirement obligations primarily represent the estimated present value of the amounts we will incur to plug, abandon and remediate our producing properties at the end of their productive lives. Significant inputs used in determining such obligations include estimates of plugging and abandonment costs, estimated future inflation rates and well life. The inputs are calculated based on historical data as well as current estimated costs.

A reconciliation of our liability for plugging and abandonment costs for the years ended December 31, 2013 and 2012 is as follows (in thousands):


	2013			2012
Beginning of period	$	146,478		$	84,810
Liabilities incurred		8,731			9,802
Liabilities settled		(424)			(3,649	)
Disposition of wells		(3,129	)		(1,457	)
Accretion expense		10,778			8,793
Change in estimate		67,643			48,179
End of period		230,077			146,478
Less current portion		(5,037	)		(2,470	)
Long-term asset retirement obligations	$	225,040		$	144,008

Accretion expense is recognized as an increase to depreciation, depletion and amortization expense in the accompanying statements of operations.