Asset Retirement Obligations

6 Months Ended

Jun. 30, 2017

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

Note 7. Asset Retirement Obligations

Asset retirement obligations consist of estimated costs of dismantlement, removal, site reclamation and similar activities associated with our infrastructure assets. Changes in asset retirement obligations are as follows:

	Six Months Ended June 30,
(in thousands)	2017		2016
Asset Retirement Obligations, Beginning Balance	$	5,415	$	3,612
Liabilities Incurred	1,566		—
Revision of Estimate	—		1,224
Accretion Expense (1)	143		87
Asset Retirement Obligations, Ending Balance	$	7,124	$	4,923

⁽¹⁾  Accretion expense is included in depreciation and amortizationexpense in the consolidated statements ofoperations.

Liabilities incurred in the 2017 period were primarily related to our Central Gathering Facility (CGF) in the Delaware Basin.

Revisions in the 2016 period were primarily due to changes in estimated costs for future abandonment activities of our gathering systems in the Wells Ranch and East Pony integrated development plan (IDP) areas.