Asset Retirement Obligations

12 Months Ended

Dec. 31, 2012

Asset Retirement Obligations [Abstract]

Asset Retirement Obligations

NOTE 7 —  ASSET RETIREMENT OBLIGATIONS

The total undiscounted amount of future cash flows to settle our asset retirement obligations is estimated to be $275.0 million and $285.0 million at December 31, 2012 and 2011. Payments to settle asset retirement obligations occur over the lives of the oil and gas properties, estimated to be from less than one year to 45 years.

Changes in the asset retirement obligations are presented in the following table:

	Year Ended		Year Ended
	December 31,		December 31,
	2012		2011
Beginning of period	$	92,561	$	69,230
Assumed in acquisitions		14,581		-
Revisions to previous estimates (1)		17,278		18,609
Liabilities incurred		1,185		377
Liabilities settled		(4,262)		(248)
Accretion expense		5,648		4,593
End of period	$	126,991	$	92,561
Less: Current portion of asset retirement obligations		(1,426)		(348)
Asset retirement obligations - non current	$	125,565	$	92,213

⁽¹⁾ In 2012, we recorded an upward revision to previous estimates for our asset retirement obligations primarily due to changes in the estimated abandonment dates. In 2011, we recorded upward revisions to previous estimates for our asset retirement obligations due to increases in future plugging and abandonment costs and changes to the remaining lives of our wells.