Supplemental Information on Natural Gas and Oil Exploration, Development and Production Activities (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization ^(a)

	December 31,
	2017			2016			2015
	(in thousands)
Natural gas and oil properties:
Properties subject to depletion	$	10,572,453		$	9,462,350		$	8,047,181
Unproved properties		2,644,000			2,923,803			949,155
Total		13,216,453			12,386,153			8,996,336
Accumulated depreciation, depletion and amortization		(3,649,716	)		(3,129,816	)		(2,635,031	)
Net capitalized costs	$	9,566,737		$	9,256,337		$	6,361,305

^(a)	Includes capitalized asset retirement costs and the associated accumulated amortization.

Costs Incurred for Property Acquisition, Exploration and Development

Costs Incurred for Property Acquisition, Exploration and Development ^(a)

	December 31,
	2017		2016			2015
	(in thousands)
Acquisitions
Acreage purchases	$	62,075	$	33,142		$	73,025
Oil and gas properties		18,269		3,098,772			—
Asset retirement obligations and other		—		21,908			—
Development		1,177,526		497,795			708,268
Exploration:
Drilling		2,030		37,680			87,505
Expense		50,920		30,027			18,421
Stock-based compensation expense		2,742		2,298			2,985
Gas gathering facilities:
Development		15,097		3,595			13,337
Subtotal		1,328,659		3,725,217			903,541
Asset retirement obligations		20,245		(24,064	)		22,184
Total costs incurred	$	1,348,904	$	3,701,153		$	925,725

^(a)

Includes cost incurred whether capitalized or expensed.

Proved Developed and Undeveloped Reserves


	Natural Gas			NGLs			Crude Oil and Condensate			Natural Gas Equivalents
	(Mmcf)			(Mbbls)			(Mbbls)			(Mmcfe) ^(a)
Proved developed and undeveloped reserves:
Balance, December 31, 2014		6,922,836			515,907			48,658			10,310,229
Revisions		(340,286	)		17,717			3,804			(211,163	)
Extensions, discoveries and additions		1,017,956			36,308			4,924			1,265,348
Property sales		(960,122	)		(441	)		(109	)		(963,423	)
Production		(362,687	)		(20,356	)		(4,084	)		(509,328	)
Balance, December 31, 2015		6,277,697			549,135			53,193			9,891,663
Revisions		(7,441	)		41,402			2,471			255,794
Extensions, discoveries and additions		1,193,154			26,991			6,506			1,394,134
Purchases		943,544			40,724			11,986			1,259,806
Property sales		(160,727	)		(360	)		(295	)		(164,655	)
Production		(375,811	)		(27,826	)		(3,609	)		(564,420	)
Balance, December 31, 2016		7,870,416			630,066			70,252			12,072,322
Revisions		70,222			83,338			(10,555	)		506,919
Extensions, discoveries and additions		2,866,103			87,572			15,997			3,487,519
Purchases		7,738			330			66			10,116
Property sales		(60,278	)		(2,356	)		(1,121	)		(81,133	)
Production		(490,552	)		(35,686	)		(4,785	)		(733,382	)
Balance, December 31, 2017		10,263,649			763,264			69,854			15,262,361
Proved developed reserves:
December 31, 2015		3,376,165			309,306			31,679			5,422,075
December 31, 2016		4,352,141			363,852			39,110			6,769,908
December 31, 2017		5,437,674			448,258			36,808			8,348,074
Proved undeveloped reserves:
December 31, 2015		2,901,533			239,828			21,514			4,469,588
December 31, 2016		3,518,275			266,214			31,143			5,302,414
December 31, 2017		4,825,975			315,006			33,046			6,914,287

^(a)	Oil and NGLs are converted to mcfe at the rate of one barrel equals six mcf based upon the approximate relative energy content of oil to natural gas, which is not indicative of the relationship of oil and natural gas prices.

Changes in Proved Undeveloped Reserves

The following details the changes in proved undeveloped reserves for 2017 (Mmcfe):

Beginning proved undeveloped reserves at December 31, 2016	5,302,414
Undeveloped reserves transferred to developed	(1,861,994	)
Revisions^(a)	308,929
Purchases/(sales)	(8,907	)
Extension and discoveries	3,173,845
Ending proved undeveloped reserves at December 31, 2017	6,914,287

^(a) Includes 668 Bcfe of proved undeveloped reserves dropped due to the five year rule which can be included in our future proved reserves as these locations are added back to our five-year development plan.

Standardized Measure of Discounted Future Net Cash Flows

The standardized measure of discounted future net cash flows relating to proved natural gas, NGLs, crude oil and condensate reserves is as follows and excludes cash flows associated with derivatives outstanding at each of the respective reporting dates. Future cash inflows are net of third party transportation, gathering and compression expense.

	As of December 31,
	2017			2016
	(in thousands)
Future cash inflows	$	43,500,054		$	27,413,864
Future costs:
Production		(18,958,695	)		(14,465,059	)
Development^(a)		(3,072,688	)		(2,647,801	)
Future net cash flows before income taxes		21,468,671			10,301,004
Future income tax expense		(3,989,459	)		(1,946,259	)
Total future net cash flows before 10% discount		17,479,212			8,354,745
10% annual discount		(10,313,998	)		(4,902,816	)
Standardized measure of discounted future net cash flows	$	7,165,214		$	3,451,929

^(a) 2017 includes $430.6 million of undiscounted future asset retirement costs estimated as of December 31, 2017, using current estimates of future abandonment costs.

Changes in Discounted Future Net Cash Flows

The following table summarizes changes in the standardized measure of discounted future net cash flows.

	December 31,
	2017			2016			2015
	(in thousands)
Revisions of previous estimates:
Changes in prices and production costs	$	2,615,825		$	(212,867	)	$	(7,231,629	)
Revisions in quantities		445,667			96,615			(868,886	)
Changes in future development and abandonment costs		(497,400	)		(314,864	)		359,540
Net change in income taxes		(706,531	)		27,842			2,173,904
Accretion of discount		372,743			302,920			1,007,027
Purchases of reserves in place		6,173			488,959			—
Additions to proved reserves from extensions, discoveries and improved recovery		2,128,135			541,095			486,478
Natural gas, NGLs and oil sales, net of production costs		(1,237,970	)		(509,174	)		(522,682	)
Development costs incurred during the period		885,803			435,928			1,033,539
Sales of reserves in place		(32,946	)		(65,538	)		(1,050,237	)
Timing and other		(266,214	)		(64,850	)		(254,218	)
Net change for the year		3,713,285			726,066			(4,867,164	)
Beginning of year		3,451,929			2,725,863			7,593,027
End of year	$	7,165,214		$	3,451,929		$	2,725,863

- Definition

Tabular disclosure of the net quantities of an enterprise's interests in proved developed and undeveloped reserves of (a) crude oil (including condensate and natural gas liquids), (b) natural gas (including coal bed methane), (c) synthetic oil, (d) synthetic gas, and (e) other nonrenewable natural resources that are intended to be upgraded during the period as of the beginning of the period, changes in quantities during the period, and as of the end of the period.

+ References + Details

- Definition

Tabular disclosure of the future net cash flows relating to proved oil and gas reserves and oil and gas subject to purchase under long-term agreements in which the enterprise participates in the operation of the properties on which the oil and gas is located or otherwise serves as the producer. This information is presented in aggregate and for each geographic area for which reserve quantities are disclosed.

+ References + Details