The following table presents a summary of the Company’s property and equipment balances as of December 31, 2014 and 2013 (in thousands).



	December 31,
	2014			2013
Oil and natural gas properties
Evaluated (subject to amortization)	$	1,617,913		$	1,090,656
Unproved and unevaluated (not subject to amortization)
Incurred in 2014	116,821			—
Incurred in 2013	62,332			82,628
Incurred in 2012	12,891			23,341
Incurred in 2011 and prior	72,375			88,337
Total unproved and unevaluated	264,419			194,306
Total oil and natural gas properties	1,882,332			1,284,962
Accumulated depletion	(596,218		)	(463,091		)
Net oil and natural gas properties	1,286,114			821,871
Other property and equipment
Computer equipment	1,110			1,044
Furniture	1,191			1,057
Software	1,733			1,456
Other equipment	332			252
Leasehold improvements	971			991
Support equipment and facilities	38,135			25,110
Total other property and equipment	43,472			29,910
Accumulated depreciation	(7,514		)	(5,904		)
Net other property and equipment	35,958			24,006
Net property and equipment	$	1,322,072		$	845,877

The following table provides a breakdown of the Company’s unproved and unevaluated property costs not subject to amortization as of December 31, 2014 and the year in which these costs were incurred (in thousands).



Description	2014		2013		2012		2011 and prior		Total
Costs incurred for
Property acquisition	$	87,207	$	62,332	$	12,800	$	72,375	$	234,714
Exploration wells	21,494		—		—		—		21,494
Development wells	8,120		—		—		—		8,120
Capitalized interest	—		—		91		—		91
Total	$	116,821	$	62,332	$	12,891	$	72,375	$	264,419

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 2014 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.

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 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 $29.6 million for 2014. Of this total, $21.5 million was associated with exploration wells and $8.1 million was associated with development wells. The Company anticipates that the entire $29.6 million associated with these wells in progress at December 31, 2014 will be transferred to the amortization base during 2015.