Quarterly report pursuant to Section 13 or 15(d)

Asset Retirement Obligations

Asset Retirement Obligations
6 Months Ended
Jun. 30, 2019
Asset Retirement Obligation [Abstract]  
Asset Retirement Obligations Asset Retirement Obligations

The table below summarizes the activity for the Company’s ARO:
Six Months Ended
June 30, 2019
Asset retirement obligations at January 1, 2019

Accretion expense

Liabilities incurred

Liabilities settled
Revisions to estimate
Asset retirement obligations at end of period

Less: Current asset retirement obligations
Long-term asset retirement obligations at June 30, 2019

Liabilities incurred include additions from acquisitions, asset swaps, and new wells drilled during the year.
Liabilities settled include the retirement of 20 wells during the year.
Dispositions are primarily attributable to the Ranger Asset Divestiture in the second quarter of 2019. See Note 3 for details about the Ranger Asset Divestiture.
Revisions to estimates were due to changes in plugging cost estimates, timing of abandonment activities, and changes in working interest of producing wells.

Certain of the Company’s operating agreements require that assets be restricted for abandonment obligations. Amounts recorded in the consolidated balance sheet at June 30, 2019 as long-term restricted investments were $3,468. These assets, which primarily include short-term U.S. Government securities, are held in abandonment trusts dedicated to pay future abandonment costs for several of the Company’s oil and natural gas properties.