Oil And Gas Properties (Tables)

9 Months Ended

Sep. 30, 2011

Oil And Gas Properties

Components Of Exploration Expenses

		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2011			2010			2011			2010
Delay rental and geological and geophysical costs	$	522		$	497		$	2,176		$	2,025
Impairment of unproved properties		1,028			—			7,668	a		—
Dry hole expense and other		(2	)		(55	)		(11	)		(245	)
Total exploration expense	$	1,548		$	442		$	9,833		$	1,780

a.   Includes the costs ($6.6 million) associated with a deepwater lease the term of which expired during the second quarter of 2011.

Changes In Asset Retirement Obligations

Asset retirement obligations at December 31, 2010	$	234,936
Liability incurred during the period		1,372
Liability settled during the period		(36,591	)
Revision in estimated cash flows		22,276
Accretion expense (included in depreciation and amortization)		11,252
Asset retirement obligations at September 30, 2011	$	233,245