Anadarko Petroleum 8-K Anadarko Announces First-quarter 2013 Results

Exhibit 99

NEWS

ANADARKO ANNOUNCES FIRST-QUARTER 2013 RESULTS

INCREASES FULL-YEAR 2013 SALES-VOLUMES GUIDANCE

HOUSTON, May 6, 2013 – Anadarko Petroleum Corporation (NYSE: APC) today announced first-quarter 2013 net income attributable to common stockholders of $460 million, or $0.91 per share (diluted). These results include certain items typically excluded by the investment community in published estimates. In total, these items decreased net income by approximately $87 million, or $0.17 per share (diluted), on an after-tax basis.⁽¹⁾ Cash flow from operating activities in the first quarter of 2013 was approximately $2.503 billion, and discretionary cash flow totaled $2.056 billion.⁽²⁾

FIRST-QUARTER 2013 HIGHLIGHTS

— Achieved record daily sales volumes of 793,000 barrels of oil equivalent (BOE)

— Monetized assets totaling more than $1.2 billion

— Initiated oil production at the El Merk project in Algeria

— Delivered outstanding deepwater success in the Gulf of Mexico’s Shenandoah Basin

“The record first-quarter 2013 results reflect our commitment to accelerate value by increasing production in our core operating areas, selectively monetizing assets and delivering large-scale projects on budget,” said Anadarko President and CEO Al Walker. “We achieved a 16-percent year-over-year increase in oil sales volumes, primarily driven by 25,000 barrels-per-day growth from our U.S. onshore assets, plus the benefit of an accelerated tanker lifting at Jubilee. In addition, we monetized more than $1.2 billion of assets, including the $860 million carried-interest agreement at Heidelberg, and achieved first oil at our El Merk development in Algeria. I’m also very proud of our very active global deepwater exploration program that continues to deliver industry-leading success and differentiating value.”

OPERATIONS SUMMARY

Anadarko reported total sales volumes of 71 million BOE, or 793,000 BOE per day, during the first quarter. Liquids sales volumes averaged 345,000 BOE per day, which includes 257,000 barrels of oil per day. Natural gas volumes averaged approximately 2.7 billion cubic feet per day. As a result of this

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performance, Anadarko has increased its full-year 2013 sales-volumes guidance to a range of 279 to 287 million BOE from a previous range of 279 to 285 million BOE.

Anadarko’s Wattenberg field achieved record quarterly sales volumes, averaging more than 113,000 BOE per day, which included a 45-percent increase in liquids sales volumes over the first quarter of 2012. The Eagleford Shale also delivered record performance and surpassed a production milestone of 50 million BOE during the quarter, with total liquids sales volumes averaging approximately 28,000 barrels per day, representing a 60-percent increase over the first quarter of 2012. Anadarko also achieved record sales volumes during the quarter in the Marcellus Shale, the East Texas Horizontal play and in its Permian oil assets.

During the quarter, Anadarko and its partners achieved first oil at the El Merk project in Algeria. Production from El Merk is expected to steadily increase throughout 2013 to a net 30,000 barrels of oil per day as additional production facilities and fields are brought on line.

EXPLORATION SUMMARY

Anadarko and its partners announced two new successful deepwater wells in the Gulf of Mexico’s emerging Shenandoah Basin. Anadarko’s Shenandoah-2 well, located in Walker Ridge block 51, encountered more than 1,000 net feet of oil pay, establishing Shenandoah as one of the company’s largest Gulf of Mexico oil discoveries to date. In addition, the Coronado well, located in Walker Ridge block 98, encountered more than 400 net feet of oil pay, while drilling activity at the nearby Yucatan well in Walker Ridge block 95 is ongoing. Subsequent to quarter end, Anadarko announced the Phobos discovery, located in Sigsbee Escarpment block 39. The well encountered approximately 250 net feet of oil pay in the Wilcox formation, and future appraisal activity is now being evaluated.

Offshore Mozambique, Anadarko discovered a new, distinct natural gas reservoir in its Offshore Area 1 block. The Orca-1 discovery well, announced in April, encountered more than 190 net feet of natural gas pay and provides additional options and flexibility for future development.

The company is continuing its active worldwide deepwater exploration program with six deepwater wells currently drilling.

FINANCIAL SUMMARY

Anadarko ended the quarter with approximately $3.7 billion of cash on hand and also improved its net-debt-to-adjusted-capitalization ratio⁽²⁾ to 32 percent at the end of the first quarter compared to 34 percent at the end of 2012. In addition to the $1.2 billion of monetizations, Anadarko also completed the sale of

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its Liberty and Rome natural gas gathering systems in the Marcellus Shale to its subsidiary, Western Gas Partners, LP (NYSE: WES), for total consideration of $490 million.

OPERATIONS REPORT

For more details on Anadarko’s operations and exploration program, please refer to the comprehensive report on first-quarter 2013 activity. The report is available atwww.anadarko.com on the Investor Relations page.

CONFERENCE CALLTOMORROWAT 9A.M. CDT, 10A.M. EDT

Anadarko will host a conference call on Tuesday, May 7, 2013, at 9 a.m. Central Daylight Time (10 a.m. Eastern Daylight Time) to discuss first-quarter results, current operations and the company’s outlook for the remainder of 2013. The dial-in number is 855.812.0464 in the United States, or 970.300.2271 internationally. The confirmation number is 36701180. For complete instructions on how to participate in the conference call, or to listen to the live audio webcast and slide presentation, please visit www.anadarko.com. A replay of the call will be available on the website for approximately 30 days following the conference call.

FINANCIAL DATA

Eight pages of summary financial data follow, including current hedge positions and updated financial and production guidance.

⁽¹⁾See the accompanying table for details of certain items affecting comparability.

⁽²⁾See the accompanying table for a reconciliation of GAAP to non-GAAP financial measures and a statement indicating why management believes the non-GAAP financial measures provide useful information for investors.

Anadarko Petroleum Corporation’s mission is to deliver a competitive and sustainable rate of return to shareholders by exploring for, acquiring and developing oil and natural gas resources vital to the world’s health and welfare. As of year-end 2012, the company had approximately 2.56 billion barrels-equivalent of proved reserves, making it one of the world’s largest independent exploration and production companies. For more information about Anadarko and APC Flash Feed updates, please visitwww.anadarko.com.

This news release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Anadarko believes that its expectations are based on reasonable assumptions. No assurance, however, can be given that such expectations will prove to have been correct. A number of factors could cause actual results to differ materially from the projections, anticipated results or other expectations expressed in this news release, including Anadarko’s ability to drill, develop and commercially operate the drilling prospects identified in this news release. See “Risk Factors” in the company’s

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2012 Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and other public filings and press releases. Anadarko undertakes no obligation to publicly update or revise any forward-looking statements.

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ANADARKO CONTACTS

MEDIA:

John Christiansen,john.christiansen@anadarko.com, 832.636.8736

Brian Cain,brian.cain@anadarko.com, 832.636.3404

Christina Ramirez,christina.ramirez@anadarko.com, 832.636.8687

INVESTORS:

John Colglazier,john.colglazier@anadarko.com, 832.636.2306

Brian Kuck,brian.kuck@anadarko.com, 832.636.1397

Bill Tedesco,william.tedesco@anadarko.com, 832.636.3375

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Anadarko Petroleum Corporation

Certain Items Affecting Comparability

	Quarter Ended March 31, 2013
millions except per-share amounts	Before Tax		After Tax		Per Share   (diluted)
Unrealized gains (losses) on derivatives, net*	$	(246)	$	(156)	$	(0.31)
Gains (losses) on divestitures, net		144		90		0.18
Impairments		(29)		(19)		(0.04)
Algeria exceptional profits tax settlement		(33)		—		—
Deepwater Horizon settlement and related costs		(3)		(2)		—
	$	(167)	$	(87)	$	(0.17)

* For the quarter ended March 31, 2013, before-tax unrealized gains (losses) on derivatives, net includes $(334) million related to commodity derivatives, $92 million related to other derivatives, and $(4) million related to gathering, processing, and marketing sales.

	Quarter Ended March 31, 2012
millions except per-share amounts	Before Tax		After Tax		Per Share   (diluted)
Unrealized gains (losses) on derivatives, net*	$	142	$	90	$	0.18
Gains (losses) on divestitures, net		(17)		(11)		(0.02)
Impairments, including unproved properties		(53)		(34)		(0.07)
Change in uncertain tax positions (FIN 48)		—		12		0.03
Algeria exceptional profits tax settlement		1,804		1,804		3.60
Tronox damage claim settlement		(275)		(175)		(0.35)
Deepwater Horizon settlement and related costs		(8)		(5)		(0.01)
	$	1,593	$	1,681	$	3.36

* For the quarter ended March 31, 2012, before-tax unrealized gains (losses) on derivatives, net includes $(89) million related to commodity derivatives, $236 million related to other derivatives, and $(5) million related to gathering, processing, and marketing sales.

Reconciliation of GAAP to Non-GAAP Measures

Below are reconciliations of cash provided by operating activities (GAAP) to discretionary cash flow from operations (non-GAAP), free cash flow (non-GAAP), and adjusted free cash flow (non-GAAP), as well as net income (loss) attributable to common stockholders (GAAP) to adjusted net income (loss) (non-GAAP) as required under Regulation G of the Securities Exchange Act of 1934. Management uses discretionary cash flow from operations because it is useful in comparisons of oil and gas exploration and production companies as it excludes fluctuations in assets and liabilities. Management uses free cash flow and adjusted free cash flow to demonstrate the Company’s ability to internally fund capital expenditures and to service or incur additional debt. Management uses adjusted net income (loss) to evaluate the Company’s operational trends and performance.

	Quarter Ended     March 31,
millions	2013		2012
Net cash provided by operating activities	$	2,503	$	1,891
Add back
Deepwater Horizon settlement and related costs		3		(22)
Algeria exceptional profits tax settlement		(450)		—
Change in accounts receivable		(40)		27
Change in accounts payable and accrued expenses		158		258
Change in other items—net		(118)		(232)
Discretionary cash flow from operations	$	2,056	$	1,922

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Anadarko Petroleum Corporation

Reconciliation of GAAP to Non-GAAP Measures

	Quarter Ended            March 31,
millions	2013		2012
Discretionary cash flow from operations	$	2,056	$	1,922
Less capital expenditures*		1,747		1,790
Free cash flow	$	309	$	132
Collection of Algeria exceptional profits tax receivable		450		—
Adjusted free cash flow	$	759	$	132

* Includes Western Gas Partners, LP (WES) capital expenditures of $299 million and $98 million for the three months ended March 31, 2013 and 2012, respectively.

	Quarter Ended March 31, 2013						Quarter Ended      March 31, 2012
millions except per-share amounts	After     Tax			Per Share (diluted)			After Tax		Per Share  (diluted)
Net income (loss) attributable to common stockholders	$	460		$	0.91		$	2,156	$	4.28
Certain items affecting comparability		(87	)		(0.17	)		1,681		3.36
Adjusted net income (loss)	$	547		$	1.08		$	475	$	0.92

Presented below is a reconciliation of total debt (GAAP) to net debt (non-GAAP). Management uses net debt as a measure of the Company’s outstanding debt obligations that would not be readily satisfied by its cash and cash equivalents on hand.

millions	March 31, 2013
Total debt	$	13,663
Less cash and cash equivalents		3,735
Net debt	$	9,928
Net debt	$	9,928
Stockholders’ equity		21,090
Adjusted capitalization	$	31,018
Net debt to adjusted capitalization ratio		32%

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Anadarko Petroleum Corporation

(Unaudited)

Summary Financial Information	Quarter Ended     March 31,
millions except per-share amounts	2013		2012
Consolidated Statements of Income
Revenues and Other
Natural-gas sales	$	807	$	573
Oil and condensate sales		2,377		2,244
Natural-gas liquids sales		303		342
Gathering, processing, and marketing sales		231		253
Gains (losses) on divestitures and other, net		175		35
Total		3,893		3,447
Costs and Expenses
Oil and gas operating		247		242
Oil and gas transportation and other		255		240
Exploration		264		244
Gathering, processing, and marketing		199		189
General and administrative		272		269
Depreciation, depletion, and amortization		1,022		930
Other taxes		280		377
Impairments		29		50
Algeria exceptional profits tax settlement		33		(1,804)
Deepwater Horizon settlement and related costs		3		8
Total		2,604		745
Operating Income (Loss)		1,289		2,702
Other (Income) Expense
Interest expense		164		186
(Gains) losses on derivatives, net		191		(284)
Other (income) expense, net		(6)		265
Total		349		167
Income (Loss) Before Income Taxes		940		2,535
Income Tax Expense (Benefit)		456		352
Net Income (Loss)	$	484	$	2,183
Net Income Attributable to Noncontrolling Interests		24		27
Net Income (Loss) Attributable to Common Stockholders	$	460	$	2,156
Per Common Share
Net income (loss) attributable to common stockholders—basic	$	0.91	$	4.30
Net income (loss) attributable to common stockholders—diluted	$	0.91	$	4.28
Average Number of Common Shares Outstanding—Basic		501		499
Average Number of Common Shares Outstanding—Diluted		503		501
Exploration Expense
Dry hole expense	$	158	$	89
Impairments of unproved properties		19		60
Geological and geophysical expense		37		35
Exploration overhead and other		50		60
Total	$	264	$	244

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Anadarko Petroleum Corporation

(Unaudited)

Summary Financial Information	Quarter Ended March 31,
millions	2013		2012
Cash Flows from Operating Activities
Net income (loss)	$	484	$	2,183
Depreciation, depletion, and amortization		1,022		930
Deferred income taxes		162		210
Dry hole expense and impairments of unproved properties		177		149
Impairments		29		50
(Gains) losses on divestitures, net		(144)		17
Unrealized (gains) losses on derivatives, net		246		(142)
Deepwater Horizon settlement and related costs		3		8
Algeria exceptional profits tax settlement		33		(1,804)
Tronox-related contingent loss		—		275
Other		44		46
Discretionary Cash Flow from Operations		2,056		1,922
Deepwater Horizon settlement and related costs		(3)		22
Algeria exceptional profits tax settlement		450		—
(Increase) decrease in accounts receivable		40		(27)
Increase (decrease) in accounts payable and accrued expenses		(158)		(258)
Other items—net		118		232
Net Cash Provided by Operating Activities	$	2,503	$	1,891
Capital Expenditures	$	1,747	$	1,790
millions	March 31, 2013		December 31, 2012
Condensed Balance Sheets
Cash and cash equivalents	$	3,735	$	2,471
Accounts receivable, net of allowance		2,760		2,747
Algeria exceptional profits tax settlement		280		730
Other current assets		535		847
Net properties and equipment		38,970		38,398
Other assets		1,630		1,716
Goodwill and other intangible assets		5,678		5,680
Total Assets	$	53,588	$	52,589
Current asset retirement obligations		387		298
Other current liabilities		3,685		3,696
Long-term debt		13,663		13,269
Deferred income taxes		8,964		8,759
Other long-term liabilities		4,559		4,685
Stockholders’ equity		21,090		20,629
Noncontrolling interests		1,240		1,253
Total Liabilities and Equity	$	53,588	$	52,589
Capitalization
Total debt	$	13,663	$	13,269
Stockholders’ equity		21,090		20,629
Total	$	34,753	$	33,898
Capitalization Ratios
Total debt		39%		39%
Stockholders’ equity		61%		61%

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Anadarko Petroleum Corporation

(Unaudited)

Sales Volumes and Prices

	Average Daily Volumes						Sales Volumes								Average Sales Price
	Natural  Gas MMcf/d		Crude Oil  & Condensate MBbls/d		NGLs MBbls/d		Natural  Gas Bcf		Crude Oil  & Condensate MMBbls			NGLs MMBbls			Natural Gas Per Mcf			Crude Oil  & Condensate Per Bbl		NGLs Per Bbl
Quarter Ended March 31, 2013
United States		2,689		159		88		242		14			8		$	3.33		$	97.32	$	38.17
Algeria		—		53		—		—		5			—			—			112.91		—
Other International		—		45		—		—		4			—			—			111.32		—
Total		2,689		257		88		242		23			8		$	3.33		$	102.97	$	38.17
Quarter Ended March 31, 2012
United States		2,416		138		80		220		12			7		$	2.60		$	105.75	$	47.09
Algeria		—		50		—		—		5			—			—			119.57		—
Other International		—		33		—		—		3			—			—			120.64		—
Total		2,416		221		80		220		20			7		$	2.60		$	111.07	$	47.09
	Average Daily  Volumes MBOE/d				Sales  Volumes MMBOE
Quarter Ended March 31, 2013		793				71
Quarter Ended March 31, 2012		704				64
Sales Revenue and Commodity Derivatives
	Sales						Commodity Derivatives Gain (Loss)
			Crude Oil & Condensate				Natural Gas					Crude Oil & Condensate						NGLs
millions	Natural Gas				NGLs		Realized		Unrealized			Realized			Unrealized			Realized		Unrealized
Quarter Ended March 31, 2013
United States	$	807	$	1,393	$	303	$	67	$	(269	)	$	1		$	(60	)	$	2	$	(5	)
Algeria		—		537		—		—		—			(19	)		—			—		—
Other International		—		447		—		—		—			—			—			—		—
Total	$	807	$	2,377	$	303	$	67	$	(269	)	$	(18	)	$	(60	)	$	2	$	(5	)
Quarter Ended March 31, 2012
United States	$	573	$	1,339	$	342	$	170	$	86		$	(5	)	$	(173	)	$	—	$	(2	)
Algeria		—		538		—		—		—			(28	)		—			—		—
Other International		—		367		—		—		—			—			—			—		—
Total	$	573	$	2,244	$	342	$	170	$	86		$	(33	)	$	(173	)	$	—	$	(2	)

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Anadarko Petroleum Corporation

Financial and Operating External Guidance

As of May 6, 2013

	2nd Qtr Guidance						Total Year Guidance
	Units						Units
Total Sales (MMBOE)		67		-	69			279		-	287
Total Sales (MBOE/d)		736		-	758			764		-	786
Crude Oil (MBbl/d):		230		-	234			264		-	268
United States		154		-	158			169		-	171
Algeria		47		-	48			59		-	61
Other International		27		-	29			34		-	36
Natural Gas (MMcf/d):
United States		2,575		-	2,650			2,510		-	2,540
Natural Gas Liquids (MBbl/d):
United States		73		-	79			80		-	95
	$/Unit						$/Unit
Price Differentials vs NYMEX (w/o hedges)
Crude Oil ($/Bbl):		3.00		-	6.00			5.00		-	8.00
United States		1.00		-	3.00			1.00		-	3.00
Algeria		10.00		-	12.00			12.00		-	15.00
Other International		10.00		-	12.00			10.00		-	13.00
Natural Gas ($/Mcf):
United States		(0.05	)	-	(0.15	)		(0.05	)	-	(0.15	)

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Anadarko Petroleum Corporation

Financial and Operating External Guidance

As of May 6, 2013

	2nd Qtr Guidance						Total Year Guidance *
	$MM						$MM
Other Revenues:
Marketing and Gathering Margin		25		-	35			150		-	170
Minerals and Other		25		-	35			120		-	140
Costs and Expenses:
	$/BOE						$/BOE
Oil & Gas Direct Operating		4.00		-	4.20			3.90		-	4.05
Oil & Gas Transportation/Other		3.75		-	3.95			3.55		-	3.75
Depreciation, Depletion and Amortization		14.25		-	14.50			14.50		-	14.75
Production Taxes (% of Product Revenue)		7.5	%	-	8.5	%		7.5	%	-	9.5	%
	$MM						$MM
General and Administrative		280		-	290			1,050		-	1,150
Exploration Expense
Non-Cash		150		-	175			900		-	1,000
Cash		105		-	115			475		-	525
Interest Expense (net)		185		-	190			710		-	720
Other (Income)/Expense		15		-	25			75		-	95
Tax Rate:
Algeria (All current)		45	%	-	50	%		45	%	-	50	%
Rest of Company (10% Current for 2Q and 20% for FY)		45	%	-	55	%		45	%	-	55	%
Avg. Shares Outstanding (MM):
Basic		501		-	502			502		-	503
Diluted		504		-	505			504		-	505
Capital Investment (Excluding Western Gas Partners, LP):	$MM						$MM
APC Capital Expenditures		1,700		-	1,900			7,200		-	7,600

* Excludes items affecting comparability

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Anadarko Petroleum Corporation

Commodity Hedge Positions (Excluding Natural Gas Basis)

As of May 6, 2013

				��
	Volume (MBbl/d)	Weighted Average Price per Barrel
		Floor Sold	Floor Purchased	Ceiling Sold
Crude Oil
Three-Way Collars
2013
Brent	26	$              85.00	$            105.00	$            125.15
Fixed Price - Financial
2013
Brent	61	$            108.72
WTI	47	$              94.43
	108	$            102.50
	Volume (thousand MMBtu/d)	Weighted Average Price per MMBtu
		Floor Sold	Floor Purchased	Ceiling Sold
Natural Gas
Two-Way Collars
2013 (April - October)	600	n/a	$                3.18	$                4.00
Three-Way Collars
2014	600	$                2.75	$                3.75	$                5.01
Fixed Price - Financial
2013	1,185	$                4.00
2014	600	$                4.26

Interest Rate Derivatives

As of May 6, 2013

Instrument	Notional Amt.	Start Date	Maturity	Rate Paid	Rate Received
Swap	$750 Million	June 2014	June 2024	6.00%	3M LIBOR
Swap	$1,100 Million	June 2014	June 2044	5.57%	3M LIBOR
Swap	$50 Million	Sept. 2016	Sept. 2026	5.91%	3M LIBOR
Swap	$750 Million	Sept. 2016	Sept. 2046	5.86%	3M LIBOR