Oil And Gas Properties (Tables)

9 Months Ended

Sep. 30, 2012


		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2012		2011		2012		2011

Delay rental and geological and geophysical costs	$	623	$	522	$	2,380	$	2,176
Impairment of unproved properties ⁽¹⁾		-		1,028		144		7,668
Dry hole expense		-		(1)		(55)		(11)
Total exploration expense	$	623	$	1,549		2,469		9,833

(1) Included in the nine-month period ended September 30, 2011 were costs of $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 obligation at December 31, 2011	$	254,391
Liability incurred during the period		1,110
Liability settled during the period		(108,729)
Other revisions in estimated cash flows ⁽¹⁾		47,080
Accretion expense (included in depreciation and amortization)		9,743
Asset retirement obligations at September 30, 2012	$	203,595

(1) The increased amount of these liabilities includes revisions to both non-producing and producing oil and gas properties. Increases to liabilities associated with non-producing properties ($24.9 million) include a corresponding charge to cost of sales within our condensed consolidated statements of operations and comprehensive income while changes in estimates for producing properties are recorded as an increase to property and equipment carrying costs of the related oil and gas properties within our condensed consolidated balance sheets.