The following table presents a summary of the Company’s property and equipment balances as of December 31, 2013 and 2012 (in thousands).



	December 31,
	2013			2012
Oil and natural gas properties
Evaluated (subject to amortization)	$	1,090,656		$	763,527
Unproved and unevaluated (not subject to amortization)
Incurred in 2013	82,628			—
Incurred in 2012	23,341			36,488
Incurred in 2011	10,982			24,138
Incurred in 2010 and prior	77,355			89,049
Total unproved and unevaluated	194,306			149,675
Total oil and natural gas properties	1,284,962			913,202
Accumulated depletion	(463,091		)	(344,609		)
Net oil and natural gas properties	821,871			568,593
Other property and equipment
Computer equipment	1,044			834
Furniture	1,057			793
Software	1,456			1,355
Other equipment	252			196
Leasehold improvements	991			644
Support equipment and facilities	25,110			23,436
Total other property and equipment	29,910			27,258
Accumulated depreciation	(5,904		)	(4,761		)
Net other property and equipment	24,006			22,497
Net property and equipment	$	845,877		$	591,090

The following table provides a breakdown of the Company’s unproved and unevaluated property costs not subject to amortization as of December 31, 2013 and the year in which these costs were incurred (in thousands).



Description	2013		2012		2011		2010 and prior		Total
Costs incurred for
Property acquisition	$	66,582	$	22,944	$	9,050	$	77,355	$	175,931
Exploration wells	12,901		247		1,932		—		15,080
Development wells	3,145		—		—		—		3,145
Capitalized interest	—		150		—		—		150
Total	$	82,628	$	23,341	$	10,982	$	77,355	$	194,306

Property acquisition costs primarily include leasehold costs paid to secure oil and natural gas mineral leases, but may also include broker and legal expenses, geological and geophysical expenses and capitalized internal costs associated with developing oil and natural gas prospects on these properties. Property acquisition costs are transferred into the amortization base on an ongoing basis as these properties are evaluated and proved reserves are established or impairment is determined. Unproved and unevaluated properties are assessed for possible impairment on a periodic basis based upon changes in operating or economic conditions.

Property acquisition costs incurred in 2013 were related primarily to the Company’s leasehold acquisitions in the Wolfcamp and Bone Spring plays in the Permian Basin in Southeast New Mexico and West Texas, but also include costs associated with additional leasehold acquisitions in the Eagle Ford shale play in South Texas and the Haynesville shale play in Northwest Louisiana and East Texas.

Property acquisition costs incurred in 2012 were related primarily to the Company’s leasehold acquisitions in the Eagle Ford shale play in South Texas and the Wolfcamp and Bone Spring plays in the Permian Basin in Southeast New Mexico and West Texas. Property acquisition costs incurred in 2011 were related primarily to the Company’s leasehold acquisitions in the Eagle Ford shale play in South Texas. These costs are associated with acreage for which proved reserves have yet to be assigned. As the Company drills wells and assigns proved reserves to these properties or determines that certain portions of this acreage, if any, cannot be assigned proved reserves, portions of these costs are transferred to the amortization base. The Company estimates that the evaluation of most of these properties and the inclusion of their costs in the amortization base should be completed within three to five years or less.

Property acquisition costs incurred in 2010 and prior years were related primarily to the Company’s leasehold acquisitions in the Eagle Ford shale play in South Texas and in the Haynesville shale play in Northwest Louisiana. These costs are associated with acreage for which proved reserves have yet to be assigned. Almost all of these costs are associated with properties which are held by production and have no near-term expiration risk. As the Company drills wells and assigns proved reserves to these properties or determines that certain portions of this acreage, if any, cannot be assigned proved reserves, portions of these costs are transferred to the amortization base. The Company estimates that evaluation of most of these properties and the inclusion of their costs in the amortization base should be completed within three to five years or less.

Costs excluded from amortization also include those costs associated with exploration and development wells in progress or awaiting completion at year-end. These costs are transferred into the amortization base on an ongoing basis as these wells are completed and proved reserves are established or confirmed. These costs totaled $16.0 million for 2013. Of this total, $12.9 million was associated with exploration wells and $3.1 million was associated with development wells. The Company anticipates that the entire $16.0 million associated with these wells in progress at December 31, 2013 will be transferred to the amortization base during 2014. At December 31, 2013, there were $2.2 million in exploratory well costs excluded from amortization that were incurred in years prior to 2013, all associated with the Company’s initial exploration well in the Meade Peake shale in Southwest Wyoming. The Company completed the horizontal lateral section of this exploratory well during the fall of 2013, but initial testing was still in progress at December 31, 2013. The Company plans to finalize the testing of this well in 2014 and expects that all exploration costs incurred on this well will be transferred to the amortization base during 2014.