Property and equipment, net

Property and equipment, net is comprised of the following:



	December 31,			December 31,
	2019			2018
	(In thousands)
Proved oil and natural gas properties	$	1,013,952		$	777,558
Unproved oil and natural gas properties	97,706			121,929
Land	1,575			1,575
Less: accumulated DD&A and impairment	(368,636		)	(234,265		)
Total oil and natural gas properties (successful efforts), net	744,597			666,797
Other property and equipment	7,348			6,059
Less: accumulated DD&A	(4,364		)	(3,467		)
Total other property and equipment, net	2,984			2,592
Total property and equipment, net	$	747,581		$	669,389

As the Company’s exploration and development work progresses and the reserves on the Company’s properties are proven, capitalized costs attributed to the properties and mineral interests are subject to DD&A. Depletion of capitalized costs is provided using the units-of-production method based on proved oil and gas reserves related to the associated field. DD&A was $136.2 million, $140.4 million and $35.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. Depreciation and amortization expense related to other property and equipment was $0.9 million, $0.7 million and $0.4 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Costs not subject to DD&A primarily include leasehold costs, broker and legal expenses and capitalized internal costs associated with developing oil and natural gas prospects on these properties. Leasehold costs are transferred into costs subject to depletion on an ongoing basis as these properties are evaluated and proved reserves are established. Additionally, costs associated with development wells in progress or awaiting completion at year-end are not subject to DD&A. These costs are transferred into costs subject to DD&A on an ongoing basis as these wells are completed and proved reserves are established or confirmed. Capitalized costs included in proved oil and natural gas properties not subject to DD&A totaled $19.9 million at December 31, 2019 and $87.1 million at December 31, 2018.

There were no impairment charges to proved oil and natural gas properties for the years ended December 31, 2019 and 2018 and $1.1 million for the year ended December 31, 2017. There was $12.4 million of impairment charges to unproved oil and natural gas properties for the year ended December 31, 2019, primarily related to expiring leases, and none for the years ended December 31, 2018 and 2017. There were no exploratory well costs pending determination of proved reserves for the years ended December 31, 2019 and 2018. There were no unsuccessful exploratory dry hole costs during the years ended December 31, 2019 and 2018. Unsuccessful exploratory dry hole costs were $0.2 million for the year ended December 31, 2017.

Acquisitions and Divestitures

Pecos County, Texas Farm-in Agreement. On February 27, 2019, Rosehill entered into a farm-in agreement that would allow it to earn approximately 2,200 net acres contiguous to its core areas in the Southern Delaware Basin subject to its obligation to drill and complete up to seven wells through 2020 and carrying 25% of the drilling and completion costs for each of the seven wells and the costs of facilities and equipment. See Note 17 - Commitments and Contingencies for more details on the commitments associated with the agreement.

Other Acquisitions. In 2018, the Company paid approximately $15.3 million to acquire additional working interests, surface rights and additional royalty interests in our core areas throughout the Delaware Basin. In 2017, the Company purchased additional working interests in various operated wells and leasehold interests in Loving County, Texas for total consideration of $6.5 million.

White Wolf Acquisition. In December 2017, the Company acquired mineral rights and royalty interest to approximately 6,505 net acres in the Southern Delaware Basin (the “White Wolf Acquisition”) for approximately $116.6 million, subject to customary purchase price adjustments. The Company incurred transaction fees of $2.9 million and acquired approximately $1.6 million of abandonment liability related to assets that were attached to the acreage acquired. Total consideration paid and capitalized in connection with the White Wolf Acquisition was $121.1 million. The Company accounted for the White Wolf Acquisition as an asset acquisition.

Divestiture of Lea County, New Mexico Assets. On March 26, 2019, Rosehill signed a Purchase and Sale Agreement to sell all of its rights, title and interests to all leases, wells, facilities, easements and contracts located in Lea County, New Mexico for net proceeds of $21.8 million, along with the assumption by the purchaser of all abandonment obligations associated with the properties. On April 4, 2019, Rosehill closed the transaction, and the Company recorded a gain of approximately $11.1 million upon closing of the divestiture. The divestiture of the Lea County, New Mexico assets did not represent a strategic shift with a major effect on the Company’s operations and financial results, therefore, was not reported as a discontinued operation.

Barnett Shale Divestiture. On November 2, 2017, the Company consummated the sale of Barnett Shale assets for net proceeds of approximately $6.5 million and recorded a gain of approximately $5.3 million. The divestiture of the Barnett Shale assets did not represent a strategic shift with a major effect on the Company’s operations and financial results, therefore, was not reported as a discontinued operation.