The following table provides certain information about the operations of each of our segments:



	Year Ended December 31, 2017
	Oil and Natural Gas		Contract Drilling			Mid-stream		Other			Eliminations			Total Consolidated
	(In thousands)
Revenues:
Oil and natural gas	$	357,744	$	—		$	—	$	—		$	—		$	357,744
Contract drilling	—		188,172			—		—			(13,452		)	174,720
Gas gathering and processing	—		—			277,049		—			(69,873		)	207,176
Total revenues	357,744		188,172			277,049		—			(83,325		)	739,640
Expenses:
Operating costs:
Oil and natural gas	135,532		—			—		—			(4,743		)	130,789
Contract drilling	—		134,432			—		—			(11,832		)	122,600
Gas gathering and processing	—		—			220,613		—			(65,130		)	155,483
Total operating costs	135,532		134,432			220,613		—			(81,705		)	408,872
Depreciation, depletion, and amortization	101,911		56,370			43,499		7,477			—			209,257
Total expenses	237,443		190,802			264,112		7,477			(81,705		)	618,129
Total operating income (loss) ⁽¹⁾	120,301		(2,630		)	12,937		(7,477		)	(1,620		)
General and administrative expense	—		—			—		(38,087		)	—			(38,087		)
Gain (loss) on disposition of assets	228		(776		)	25		850			—			327
Gain on derivatives	—		—			—		14,732			—			14,732
Interest expense, net	—		—			—		(38,334		)	—			(38,334		)
Other	—		—			—		21			—			21
Income (loss) before income taxes	$	120,529	$	(3,406	)	$	12,962	$	(68,295	)	$	(1,620	)	$	60,170

Identifiable assets:
Oil and natural gas ⁽²⁾	$	1,127,900	$	—		$	—	$	—		$	—		$	1,127,900
Contract drilling	—		933,063			—		—			—			933,063
Gas gathering and processing	—		—			438,571		—			—			438,571
Total identifiable assets ⁽³⁾	1,127,900		933,063			438,571		—			—			2,499,534
Corporate land and building	—		—			—		56,854			—			56,854
Other corporate assets ⁽⁴⁾	—		—			—		25,064			—			25,064
Total assets	$	1,127,900	$	933,063		$	438,571	$	81,918		$	—		$	2,581,452

Capital expenditures:	$	270,443	$	36,148		$	22,168	$	3,521		$	—		$	332,280

_______________________


(1)	Operating income (loss) is total operating revenues less operating expenses, depreciation, depletion, and amortization and does not include general corporate expenses, gain (loss) on disposition of assets, gain on derivatives, interest expense, other income, or income taxes.


(2)	Oil and natural gas assets include oil and natural gas properties, saltwater disposal systems, and other non-full cost pool assets.


(3)	Identifiable assets are those used in Unit’s operations in each industry segment.


(4)	Corporate assets are principally cash and cash equivalents, short-term investments, transportation equipment, furniture, and equipment.



	Year Ended December 31, 2016
	Oil and Natural Gas			Contract Drilling			Mid-stream			Other			Eliminations			Total Consolidated
	(In thousands)
Revenues:
Oil and natural gas	$	294,221		$	—		$	—		$	—		$	—		$	294,221
Contract drilling	—			122,086			—			—			—			122,086
Gas gathering and processing	—			—			237,785			—			(51,915		)	185,870
Total revenues	294,221			122,086			237,785			—			(51,915		)	602,177
Expenses:
Operating costs:
Oil and natural gas	126,739			—			—			—			(6,555		)	120,184
Contract drilling	—			88,154			—			—			—			88,154
Gas gathering and processing	—			—			182,969			—			(45,360		)	137,609
Total operating costs	126,739			88,154			182,969			—			(51,915		)	345,947
Depreciation, depletion and amortization	113,811			46,992			45,715			1,835			—			208,353
Impairments ⁽¹⁾	161,563			—			—			—			—			161,563
Total expenses	402,113			135,146			228,684			1,835			(51,915		)	715,863
Total operating income (loss) ⁽²⁾	(107,892		)	(13,060		)	9,101			(1,835		)	—
General and administrative expense	—			—			—			(33,337		)	—			(33,337		)
Gain (loss) on disposition of assets	(324		)	3,184			(302		)	(18		)	—			2,540
Loss on derivatives	—			—			—			(22,813		)	—			(22,813		)
Interest expense, net	—			—			—			(39,829		)	—			(39,829		)
Other	—			—			—			307			—			307
Income (loss) before income taxes	$	(108,216	)	$	(9,876	)	$	8,799		$	(97,525	)	$	—		$	(206,818	)

Identifiable assets:
Oil and natural gas ⁽³⁾	$	965,159		$	—		$	—		$	—		$	—		$	965,159
Contract drilling	—			941,676			—			—			—			941,676
Gas gathering and processing	—			—			461,600			—			—			461,600
Total identifiable assets ⁽⁴⁾	965,159			941,676			461,600			—			—			2,368,435
Corporate land and building	—			—			—			58,188			—			58,188
Other corporate assets ⁽⁵⁾	—			—			—			52,680			—			52,680
Total assets	$	965,159		$	941,676		$	461,600		$	110,868		$	—		$	2,479,303

Capital expenditures:	$	89,562		$	19,134		$	16,796		$	16,663		$	—		$	142,155

_______________________


(1)	We incurred non-cash ceiling test write-down of our oil and natural gas properties of $161.6 million pre-tax ($100.6 million, net of tax).


(2)	Operating income (loss) is total operating revenues less operating expenses, depreciation, depletion, amortization, and impairment and does not include general corporate expenses, gain (loss) on disposition of assets, loss on derivatives, interest expense, other income (loss), or income taxes.


(3)	Oil and natural gas assets include oil and natural gas properties, saltwater disposal systems, and other non-full cost pool assets.


(4)	Identifiable assets are those used in Unit’s operations in each industry segment.


(5)	Corporate assets are principally cash and cash equivalents, short-term investments, transportation equipment, furniture, and equipment.



	Year Ended December 31, 2015
	Oil and Natural Gas			Contract Drilling			Mid-stream			Other			Eliminations			Total Consolidated
	(In thousands)
Revenues:
Oil and natural gas	$	385,774		$	—		$	—		$	—		$	—		$	385,774
Contract drilling	—			287,767			—			—			(22,099		)	265,668
Gas gathering and processing	—			—			268,012			—			(65,223		)	202,789
Total revenues	385,774			287,767			268,012			—			(87,322		)	854,231
Expenses:
Operating costs:
Oil and natural gas	170,831			—			—			—			(4,785		)	166,046
Contract drilling	—			174,757			—			—			(18,349		)	156,408
Gas gathering and processing	—			—			221,994			—			(60,438		)	161,556
Total operating costs	170,831			174,757			221,994			—			(83,572		)	484,010
Depreciation, depletion and amortization	251,944			56,135			43,676			987			—			352,742
Impairments ⁽¹⁾	1,599,348			8,314			26,966			—			—			1,634,628
Total expenses	2,022,123			239,206			292,636			987			(83,572		)	2,471,380
Total operating income (loss) ⁽²⁾	(1,636,349		)	48,561			(24,624		)	(987		)	(3,750		)
General and administrative expense	—			—			—			(34,358		)	—			(34,358		)
Gain (loss) on disposition of assets	(147		)	(7,516		)	465			(31		)	—			(7,229		)
Gain on derivatives	—			—			—			26,345			—			26,345
Interest expense, net	—			—			—			(31,963		)	—			(31,963		)
Other	—			—			—			45			—			45
Income (loss) before income taxes	$	(1,636,496	)	$	41,045		$	(24,159	)	$	(40,949	)	$	(3,750	)	$	(1,664,309	)

Identifiable assets:
Oil and natural gas ⁽³⁾	$	1,218,036		$	—		$	—		$	—		$	—		$	1,218,036
Contract drilling	—			993,015			—			—			—			993,015
Gas gathering and processing	—			—			478,661			—			—			478,661
Total identifiable assets ⁽⁴⁾	1,218,036			993,015			478,661			—			—			2,689,712
Corporate land and building	—			—			—			49,890			—			49,890
Other corporate assets ⁽⁵⁾	—			—			—			60,240						60,240
Total assets	$	1,218,036		$	993,015		$	478,661		$	110,130		$	—		$	2,799,842

Capital expenditures:	$	267,944		$	84,802		$	63,476		$	38,065		$	—		$	454,287

_______________________

(1)

We incurred non-cash ceiling test write-down of our oil and natural gas properties of $1.6 billion pre-tax ($1.0 billion, net of tax). Impairment for contract drilling equipment includes an $8.3 million pre-tax write-down for 30 drilling rigs and other drilling equipment. Impairment for gas gathering and processing systems includes $27.0 million pre-tax write-down for three of our systems, Bruceton Mills, Midwell, and Spring Creek.


(2)	Operating income (loss) is total operating revenues less operating expenses, depreciation, depletion, amortization, and impairment and does not include general corporate expenses, gain (loss) on disposition of assets, gain on derivatives, interest expense, other income (loss), or income taxes.


(3)	Oil and natural gas assets include oil and natural gas properties, saltwater disposal systems, and other non-full cost pool assets.


(4)	Identifiable assets are those used in Unit’s operations in each industry segment.


(5)	Corporate assets are principally cash and cash equivalents, short-term investments, transportation equipment, furniture, and equipment.