Property and Equipment

12 Months Ended

Dec. 31, 2013

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, 2013 and 2012:

	December 31,
In thousands	2013			2012
Oil and natural gas properties
Proved properties	$	8,945,326		$	6,963,211
Unevaluated properties	780,481			809,154
Total	9,725,807			7,772,365
Accumulated depletion and depreciation	(3,219,500		)	(2,827,256		)
Net oil and natural gas properties	6,506,307			4,945,109
CO2 properties
CO2 properties	1,117,167			1,032,653
Accumulated depletion and depreciation	(150,968		)	(119,784		)
Net CO2 properties	966,199			912,869
Pipelines and plants
CO2 pipelines (1)	1,681,774			1,632,255
Plants	527,786			402,871
Total	2,209,560			2,035,126
Accumulated depletion and depreciation	(134,697		)	(99,185		)
Net plants and pipelines	2,074,863			1,935,941
Other property and equipment
Other property and equipment	466,969			417,207
Accumulated depletion and depreciation	(163,060		)	(134,016		)
Net other property and equipment	303,909			283,191
Net property and equipment	$	9,851,278		$	8,077,110

(1) Amounts include $48.4 million of CO₂ pipelines at December 31, 2013 that were under construction and not subject to depreciation during 2013.

A summary of the unevaluated property costs excluded from oil and natural gas properties being amortized at December 31, 2013, and the year in which the costs were incurred follows:

	December 31, 2013
	Costs Incurred During:
In thousands	2013		2012		2011		2010 and prior		Total
Property acquisition costs	$	215,822	$	109,275	$	12,543	$	317,226	$	654,866
Exploration and development	41,157		22,080		7,408		10,825		81,470
Capitalized interest	25,222		12,084		6,018		821		44,145
Total	$	282,201	$	143,439	$	25,969	$	328,872	$	780,481

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 2010 and prior were primarily related to the fair value allocated to CO₂ tertiary potential at our Cedar Creek Anticline 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, 2013.  The most significant development costs incurred during 2013, 2012 and 2011 relate to development in preparation for the CO₂ flood at Grieve field, which began in 2013. We have not yet recognized proved reserves in this field.

During 2013, we established proved reserves at Bell Creek Field and, as a result, transferred $417.6 million of costs incurred on these projects into the amortization base. 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 most 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.