Oil and Gas Properties

12 Months Ended

Dec. 31, 2019

Brigham Minerals uses the full cost method of accounting for its oil and natural gas properties. Under this method, all acquisition costs incurred for the purpose of acquiring mineral and royalty interests, including certain internal costs, are capitalized into a full cost pool. Costs associated with general corporate activities are expensed in the period incurred. Oil and gas properties consisted of the following:



	December 31,
(In thousands)	2019			2018
Oil and gas properties, at cost, using the full cost method of accounting:
Not subject to depletion	$	291,664		$	228,151
Subject to depletion	449,061			289,851
Total oil and gas properties, at cost	740,725			518,002
Less accumulated depreciation, depletion, and amortization	(61,103		)	(27,628		)
Total oil and gas properties, net	$	679,622		$	490,374

Costs not subject to depletion are as follows, by the year in which such costs were incurred:



By Year:	Total		2019		2018		2017		2016		Prior
(In thousands)
Property Acquisition costs	$	291,664	$	80,964	$	73,002	$	66,139	$	10,745	$	60,814

Capitalized costs are depleted on a unit of production basis based on proved oil and natural gas reserves. Depletion expense was $30.4 million, $13.3 million and $6.2 million for the years ended December 31, 2019, 2018 and 2017, respectively. Average depletion of proved properties was $11.22, $9.38 and $7.25 per Boe for the years ended December 31, 2019, 2018 and 2017, respectively.

The costs associated with unevaluated properties primarily consist of acquisition costs and capitalized general and administrative costs. Brigham Minerals capitalizes certain overhead expenses and other internal costs attributable to the acquisition of mineral and royalty interests as part of its investment in oil and gas properties over the periods benefitted by these activities. Capitalized costs do not include any costs related to general corporate overhead or similar activities. Capitalized costs were $7.4 million, $2.7 million and $2.1 million for the years ended December 31, 2019, 2018 and 2017, respectively.