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Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2017
Asset Retirement Obligations [Abstract]  
Schedule of Reconciliation of Beginning and Ending Aggregate Carrying Amount of Asset Retirement Obligations



 

 

 

 



 

 

 

 

(Thousands of dollars)

2017

 

2016

Balance at beginning of year

$

 781,057 

 

 825,312 

         Accretion expense

 

 42,590 

 

 46,742 

         Liabilities incurred

 

 52,331 

 

 13,690 

         Revisions of previous estimates

 

 (47,612)

 

 (4,511)

         Liabilities settled

 

 (29,111)

 

 (20,589)

         Liabilities assumed by purchaser of oil and gas assets

 

 (87,456)

 

 (91,883)

         Changes due to translation of foreign currencies

 

 10,340 

 

 12,296 

                 Balance at end of year

 

 722,139 

 

 781,057 

         Liabilities reported as held for sale at end of year1

 

– 

 

 (85,900)

         Current portion of liability at end of year2

 

 (12,840)

 

 (13,629)

                 Noncurrent portion of liability at end of year

$

 709,299 

 

 681,528 



1Liabilities held for sale related to Seal properties in Canada which were sold in January 2017.

2Included in Other accrued liabilities on the Consolidated Balance Sheet.