Investment in Oil and Gas Properties—Unaudited

The following tables disclose certain financial data relative to the Company’s oil and gas producing activities, which are located onshore and offshore in the continental United States:

Costs Incurred in Oil and Gas Property Acquisition, Exploration and Development Activities

(amounts in thousands)



	For the Year-Ended December 31,
	2013			2012			2011
Acquisition costs:
Proved (1)	$	177,880		$	352		$	2,720
Unproved (1)	35,008			15,677			43,207
Divestitures—unproved (2)	(487		)	(8,889		)	(14,461		)
Exploration costs:
Proved	34,344			72,361			92,466
Unproved	20,112			18,033			5,919
Development costs	41,328			18,740			34,400
Capitalized general and administrative and interest costs	19,911			18,961			18,210
Total costs incurred	$	328,096		$	135,235		$	182,461



	For the Year-Ended December 31,
	2013			2012			2011
Accumulated depreciation, depletion and amortization (DD&A)
Balance, beginning of year	$	(1,472,244	)	$	(1,265,603	)	$	(1,175,553	)
Provision for DD&A	(69,357		)	(59,496		)	(57,143		)
Ceiling test writedown	—			(137,100		)	(18,907		)
Sale of proved properties and other (3)	(11,443		)	(10,045		)	(14,000		)
Balance, end of year	$	(1,553,044	)	$	(1,472,244	)	$	(1,265,603	)

DD&A per Mcfe	$	1.82		$	1.75		$	1.89


(1)	During 2013, the Company closed on the Gulf of Mexico Acquisition for an aggregate cash purchase price of $188.8 million (see Note 2 - Acquisition). Additionally, the Company acquired 13,500 net unevaluated acres in Oklahoma targeting the Woodford Shale.


(2)	During 2012, the Company sold an additional portion of its Mississippian Lime acreage for $6.1 million. During 2011, the Company sold a portion of its unproved Mississippian Lime acreage for $14.5 million.

(3)

During 2013, the Company sold 50% of its saltwater disposal systems and related surface assets in the Woodford for net proceeds of approximately $10.4 million. and its non-operated Wyoming assets for a cash purchase price of $1.0 million. During 2012, the Company sold its non-operated Arkansas assets for a net cash purchase price of $8.5 million. During 2011, the Company received an additional $14 million payment associated with the achievement of certain production metrics stipulated under the joint development agreement.

At December 31, 2013 and 2012, unevaluated oil and gas properties totaled $98.4 million and $71.7 million, respectively, and were not subject to depletion. Unevaluated costs at December 31, 2013 included $11.3 million of costs related to 19 exploratory wells in progress at year-end. These costs are expected to be transferred to evaluated oil and gas properties during 2014 upon the completion of drilling. At December 31, 2012, unevaluated costs included $12.7 million related to 17 exploratory wells in progress. All of these costs were transferred to evaluated oil and gas properties during 2013. The Company capitalized $6.6 million, $7.0 million and $7.0 million of interest during 2013, 2012 and 2011, respectively. Of the total unevaluated oil and gas property costs of $98.4 million at December 31, 2013, $50.3 million, or 51%, was incurred in 2013, $12.1 million, or 12%, was incurred in 2012 and $36.0 million, or 37%, was incurred in prior years. The Company expects that the majority of the unevaluated costs at December 31, 2013 will be evaluated within the next three years, including $34.4 million that the Company expects to be evaluated during 2014.