EXPLORATORY COSTS

12 Months Ended

Dec. 31, 2016

The following table sets forth capitalized exploratory well costs and includes additions pending determination of proved reserves, reclassifications to proved reserves and costs charged to expense:



Years ended December 31, (in thousands)	2016			2015			2014
Capitalized exploratory well costs at beginning of period	$	103,588		$	119,439		$	57,600
Additions pending determination of proved reserves	344,045			634,908			946,751
Reclassifications due to determination of proved reserves	(282,637		)	(650,759		)	(882,254		)
Exploratory well costs charged to expense	—			—			(2,658		)
Capitalized exploratory well costs at end of period	$	164,996		$	103,588		$	119,439

The following table sets forth capitalized exploratory wells costs:



(in thousands)	December 31, 2016		December 31, 2015
Exploratory wells in progress (drilling rig not released)	$	14,531	$	1,760
Capitalized exploratory well costs for a period of one year or less	143,602		101,828
Capitalized exploratory well costs for a period greater than one year	6,863		—
Total capitalized exploratory well costs	$	164,996	$	103,588

At December 31, 2016, Energen had 59 gross exploratory wells either drilling or waiting on results from completion and testing in the Permian Basin. At December 31, 2016, Energen had two gross wells capitalized for a period greater than one year. These wells are scheduled for completion during 2017. No wells were capitalized for a period greater than one year as of December 31, 2015.