Asset Retirement Obligation

6 Months Ended

Jun. 30, 2011

Asset Retirement Obligation

Asset Retirement Obligation

Note 9 — Asset Retirement Obligation

Following are reconciliations of the beginning and ending asset retirement obligation for the following periods (in thousands):

	Six Months Ended June 30,
	2011			2010
Asset retirement obligation, beginning of period	$	166,858		$	150,199
Liabilities incurred		1,383			1,459
Liabilities settled		(13,812	)		(2,626	)
Property dispositions		—			(242	)
Accretion of asset retirement obligation		7,435			6,853
Changes in estimates		682			(950	)
Total asset retirement obligation		162,546			154,693
Less current portion		(47,897	)		(43,720	)
Total long-term asset retirement obligation, end of period	$	114,649		$	110,973