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USD ($)

USD ($) / shares
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&lt;div style="font-family: 'Times New Roman',Times,serif;"&gt;

&lt;div style="margin-top: 12pt; font-size: 10pt;" align="left"&gt;&lt;b&gt;5. PROPERTY, PLANT AND EQUIPMENT&lt;/b&gt; &lt;/div&gt;

&lt;div style="margin-top: 6pt; font-size: 10pt;" align="left"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;Property, plant and equipment consisted of the following: &lt;/div&gt;

&lt;div align="center"&gt;

&lt;table style="font-size: 10pt;" border="0" cellspacing="0" cellpadding="0" width="55%"&gt;
&lt;tr valign="bottom"&gt;&lt;td width="76%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="5%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="3%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="1%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="3%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="5%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="3%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="1%"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td width="3%"&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 8pt;" valign="bottom"&gt;&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td colspan="3" nowrap="nowrap" align="center"&gt;&lt;b&gt;March 31,&lt;/b&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td colspan="3" nowrap="nowrap" align="center"&gt;&lt;b&gt;December 31,&lt;/b&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 8pt;" valign="bottom"&gt;&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-bottom: #000000 1px solid;" colspan="3" nowrap="nowrap" align="center"&gt;&lt;b&gt;2011&lt;/b&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-bottom: #000000 1px solid;" colspan="3" nowrap="nowrap" align="center"&gt;&lt;b&gt;2010&lt;/b&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 8pt;" valign="bottom"&gt;&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td colspan="7" nowrap="nowrap" align="center"&gt;(In thousands)&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;Oil and gas properties&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Subject to depletion&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;$&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;4,939,775&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;$&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;4,805,161&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Unevaluated costs&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;356,566&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;304,269&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Accumulated depletion&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td nowrap="nowrap" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;(2,383,394&lt;/td&gt;
&lt;td nowrap="nowrap"&gt;)&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td nowrap="nowrap" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;(2,274,785&lt;/td&gt;
&lt;td nowrap="nowrap"&gt;)&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 1px;"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Net oil and gas properties&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;2,912,947&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;2,834,645&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;Other plant and equipment&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Pipelines and processing facilities&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;277,500&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;235,676&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;General properties&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;70,907&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;70,267&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Accumulated depreciation&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td nowrap="nowrap" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;(77,362&lt;/td&gt;
&lt;td nowrap="nowrap"&gt;)&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td nowrap="nowrap" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;(72,743&lt;/td&gt;
&lt;td nowrap="nowrap"&gt;)&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 1px;"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 30px;"&gt;Net other property and equipment&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;271,045&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;233,200&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 1px;"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 1px solid;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="background: #cceeff;" valign="bottom"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;Property, plant and equipment, net of accumulated depletion and depreciation&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;$&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;3,183,992&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;$&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/td&gt;
&lt;td align="right"&gt;3,067,845&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="font-size: 1px;"&gt;&lt;td&gt;

&lt;div style="text-indent: -15px; margin-left: 15px;"&gt;&amp;nbsp;&lt;/div&gt;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 3px double;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;
&lt;td style="border-top: #000000 3px double;" colspan="2" align="right"&gt;&amp;nbsp;&lt;/td&gt;
&lt;td&gt;&amp;nbsp;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;

&lt;div style="margin-top: 12pt; font-size: 10pt;" align="left"&gt;&lt;i&gt;Ceiling Test Analysis&lt;/i&gt; &lt;/div&gt;

&lt;div style="margin-top: 6pt; font-size: 10pt;" align="left"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;We recorded impairment expense of $49.1&amp;nbsp;million for our Canadian oil and gas properties at March&amp;nbsp;31, 2011.&amp;nbsp; We computed the March&amp;nbsp;31, 2011 ceiling amount using an AECO price of $3.59 Mcf of natural gas, calculated as the unweighted average of the preceding 12-month first-day-of-the-month prices.&amp;nbsp; The AECO natural gas price used to compute the ceiling amount at March&amp;nbsp;31, 2011 was 12% lower than the AECO price used in computing the ceiling amount at December&amp;nbsp;31, 2010.&amp;nbsp; The ceiling test prepared for our U.S.&amp;nbsp; oil and gas properties resulted in no impairment at March&amp;nbsp;31, 2011.&amp;nbsp; &lt;/div&gt;

&lt;div style="margin-top: 6pt; font-size: 10pt;" align="left"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;Notes 2 and 8 to the consolidated financial statements in our 2010 Annual Report on Form 10-K contain additional information regarding our property, plant and equipment and our quarterly ceiling test analysis.&amp;nbsp; &lt;/div&gt;&lt;/div&gt; &lt;/div&gt;</NonNumbericText><NonNumericTextHeader>5. PROPERTY, PLANT AND EQUIPMENT

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;Property, plant and equipment consisted of the following:</NonNumericTextHeader><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>us-types:textBlockItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>Disclosure of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, building and production equipment. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures. This element may be used as a single block of text to include the entire PPE disclosure, including data and tables.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher AICPA
 -Name Accounting Principles Board Opinion (APB)
 -Number 12
 -Paragraph 5

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