Property and Equipment

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment Disclosure [Text Block]

Note 4. Property and Equipment

The following table presents a summary of our net property and equipment balances as of December 31, 2014 and 2013:

	December 31,
In thousands	2014			2013
Oil and natural gas properties
Proved properties	$	9,782,337		$	8,945,326
Unevaluated properties	918,406			780,481
Total	10,700,743			9,725,807
Accumulated depletion and depreciation	(3,679,883		)	(3,219,500		)
Net oil and natural gas properties	7,020,860			6,506,307
CO2 properties
CO2 properties	1,162,538			1,117,167
Accumulated depletion and depreciation	(183,646		)	(150,968		)
Net CO2 properties	978,892			966,199
Pipelines and plants
CO2 pipelines (1)	1,733,562			1,681,774
Plants	536,002			527,786
Total	2,269,564			2,209,560
Accumulated depletion and depreciation	(182,385		)	(134,697		)
Net plants and pipelines	2,087,179			2,074,863
Other property and equipment
Other property and equipment	468,051			466,969
Accumulated depletion and depreciation	(202,738		)	(163,060		)
Net other property and equipment	265,313			303,909
Net property and equipment	$	10,352,244		$	9,851,278

(1) Amount includes $98.5 million of CO₂ pipelines at December 31, 2014 that were under construction and not subject to depreciation during 2014.

A summary of the unevaluated property costs excluded from oil and natural gas properties being amortized at December 31, 2014, and the year in which the costs were incurred follows:

	December 31, 2014
	Costs Incurred During:
In thousands	2014		2013		2012		2011 and Prior		Total
Property acquisition costs	$	6,500	$	215,822	$	102,377	$	329,840	$	654,539
Exploration and development	125,783		40,835		22,080		10,361		199,059
Capitalized interest	21,807		24,898		12,084		6,019		64,808
Total	$	154,090	$	281,555	$	136,541	$	346,220	$	918,406

Our 2013 property acquisition costs were primarily related to the fair value allocated to the purchase of additional interests in the CCA. Our 2012 property acquisition costs were primarily related to the fair value allocated to our Hartzog Draw and Thompson fields.  Property acquisition costs for 2011 and prior were primarily related to the fair value allocated to CO₂ tertiary potential at our CCA properties, acquired as part of the merger with Encore Acquisition Company ("Encore"), as well as CO₂ tertiary potential at Conroe Field. Exploration and development costs shown as unevaluated properties are primarily associated with our tertiary oil fields that are under development but did not have proved reserves at December 31, 2014.  The most significant development costs incurred during 2014 relate to development in preparation for the CO₂ floods at Webster and Grieve fields, with the more significant development costs incurred during 2013, 2012 and 2011 relating to development in preparation for the CO₂ flood at Grieve field. We have not yet recognized proved reserves in these fields.

Costs are transferred into the amortization base on an ongoing basis as projects are evaluated and proved reserves established or impairment determined.  We review the excluded properties for impairment at least annually.  We currently estimate that evaluation of the majority of these properties and the inclusion of their costs in the amortization base is expected to be completed withinfivetotenyears.  Until we are able to determine whether there are any proved reserves attributable to the above costs, we are not able to assess the future impact on the amortization rate of the full cost pool.