PROPERTIES AND EQUIPMENT Exploration, Geologic, and Geophysical Expense (Tables)

12 Months Ended

Dec. 31, 2017

Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]

Cost Incurred in Oil and Gas Property Acquisition, Exploration, and Development Activities Disclosure [Table Text Block]

Exploration Expenses. The following table presents the major components of exploration, geologic, and geophysical expense:

	Year Ended December 31,
	2017		2016		2015
	(in thousands)
Exploratory dry hole costs	$	41,297	$	—	$	—
Geological and geophysical costs, including seismic purchases	3,881		3,472		—
Operating, personnel and other	2,156		1,197		1,102
Total exploration, geologic, and geophysical expense	$	47,334	$	4,669	$	1,102

Costs incurred in crude oil and natural gas property acquisition, exploration, and development are presented below.

	Year Ended December 31,
	2017		2016		2015
	(in thousands)
Acquisition of properties: (1)
Proved properties	$	172	$	268,567	$	3,561
Unproved properties	18,914		1,843,985		15
Development costs (2)	688,165		383,336		552,104
Exploration costs: (3)
Exploratory drilling	80,103		—		—
Geological and geophysical	3,881		4,669		—
Total costs incurred (4)	$	791,235	$	2,500,557	$	555,680

__________

(1) Property acquisition costs represent costs incurred to purchase, lease, or otherwise acquire a property. Proved properties

include approximately $40.9 million of infrastructure and pipeline costs in 2016.    

(2) Development costs represent costs incurred to gain access to and prepare development well locations for drilling, drill and equip development wells, recomplete wells, and provide facilities to extract, treat, gather, and store crude oil, natural gas, and NGLs. Of these costs incurred for the years ended December 31, 2017, 2016, and 2015, $463.4 million, $204.6 million, and $207.8 million, respectively, were incurred to convert proved undeveloped reserves to proved developed reserves from the prior year end. These costs also include approximately $32.8 million of infrastructure and pipeline costs in 2017.

(3) Exploration costs represent costs incurred in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing crude oil, natural gas, and NGLs. These costs include, but are not limited to, dry hole contributions and costs of drilling and equipping exploratory wells.

(4) During the year ended 2017, we finalized our purchase price allocation for the 2016 Delaware Basin acquisition within the one year measurement period. The finalization included a reduction to our proved, undeveloped and development costs of $24.6 million. We excluded this reduction from our 2017 costs incurred as it did not relate to any cash acquisitions in 2017.