Properties, Plant and Equipment

12 Months Ended

Dec. 31, 2015

Properties, Plant and Equipment

Properties, Plant and Equipment

3. Properties, Plant and Equipment

Oil and Gas Properties

        The Company accounts for its oil and natural gas exploration and production activities under the successful efforts method of accounting. Oil and gas properties consisted of the following at December 31, 2015 and 2014:

(in thousands of dollars)	2015			2014
Mineral interests in properties
Unproved	$	75,308		$	94,526
Proved		1,031,669			1,001,194
Wells and equipment and related facilities		1,289,323			1,094,202
		2,396,300			2,189,922
Less: Accumulated depletion and impairment		(760,534	)		(551,062	)
Net oil and gas properties	$	1,635,766		$	1,638,860

        As of December 31, 2015 and 2014, we had no material capitalized costs associated with exploratory wells.

        No interest costs were capitalized in 2015. The Company capitalized less than $0.1 million in interest costs during 2014. Costs incurred to maintain wells and related equipment are charged to expense as incurred.

        Depletion of oil and gas properties amounted to $204.2 million, $180.6 million, and $113.3 million for the years ended December 31, 2015, 2014, and 2013, respectively.

        No impairments of proved or unproved properties were recorded in 2015, 2014, or 2013. Certain prior period amounts have been reclassified to conform to the current presentation, include the reclassification of Impairment of oil and gas properties to Exploration in the Consolidated Statement of Operations for the twelve months ended December 31, 2013 relating to lease abandonment charges of $14.4 million for certain leases that the Company did not plan to develop.

Other Property, Plant and Equipment

        Other property, plant and equipment consisted of the following at December 31, 2015 and 2014:

(in thousands of dollars)	2015			2014
Leasehold improvements	$	1,260		$	1,218
Furniture, fixtures, computers and software		4,090			3,727
Vehicles		1,537			988
Aircraft		910			910
Other		247			219
		8,044			7,062
Less: Accumulated depreciation and amortization		(4,171	)		(3,014	)
Net other property, plant and equipment	$	3,873		$	4,048

        Depreciation and amortization of other property, plant and equipment amounted to $1.3 million, $1.1 million, and $0.8 million during the years ended December 31, 2015, 2014 and 2013, respectively.