Asset retirement obligations

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Asset retirement obligations

Asset retirement obligations

The following table presents the balance and activity of our asset retirement obligations:

Liability for asset retirement obligations as of January 1, 2018	$	35,990
Liabilities incurred in current period	689
Liabilities settled and disposed in current period	(17,868		)
Revisions in estimated cash flows	2,452
Accretion expense	1,884
Liability for asset retirement obligations as of December 31, 2018	$	23,147
Liabilities incurred in current period	448
Liabilities settled and disposed in current period	(2,305		)
Revisions in estimated cash flows	388
Accretion expense	1,478
Liability for asset retirement obligations as of December 31, 2019	$	23,156
Less current portion included in accounts payable and accrued liabilities	2,083
Asset retirement obligations, long-term	$	21,073

Liabilities incurred include obligations related to new wells drilled and wells acquired during the period. Liabilities settled and disposed in 2018 primarily relate to our oil and natural gas property divestitures discussed in “Note 6: Acquisitions and divestitures.”

See “Note 10: Fair value measurements” for additional information regarding fair value measurements.