Exhibit 99

NEWS

ANADARKO ANNOUNCES SECOND-QUARTER RESULTS

HOUSTON, July 30, 2012 – Anadarko Petroleum Corporation (NYSE: APC) today announced a second-quarter 2012 net loss attributable to common stockholders of $380 million, or $0.76 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 $804 million, or $1.61 per share (diluted), on an after-tax basis.⁽¹⁾ Cash flow from operating activities in the second quarter of 2012 was approximately $2 billion, and discretionary cash flow totaled $1.951 billion.⁽²⁾

SECOND-QUARTER 2012 HIGHLIGHTS

“Anadarko’s positive momentum continued through the second quarter of 2012 with strong operating performance, delivering record sales volumes and enabling us to increase the midpoint of our full-year sales-volumes guidance by 3 million BOE without increasing capital,” Anadarko President and CEO Al Walker said. “With record sales volumes and significant free cash flow during the first half of the year, our deep portfolio and efficient capital allocation continues to deliver growth and value in the current price environment. We are committed to operating within cash flow and selectively accelerating the value of longer-dated projects, as we did at the Gulf of Mexico Lucius development and the Salt Creek field in Wyoming during the quarter. The execution of our strategy is expected to continue to deliver industry-leading operating performance and exploration success, offering very competitive value-creation opportunities.”

2

OPERATIONS SUMMARY

Sales volumes in the second quarter rose to a record 68 million BOE, or 742,000 BOE per day, an 8-percent increase over the second quarter of 2011. During the quarter, oil volumes averaged approximately 241,000 barrels per day, natural gas liquids averaged 77,000 barrels per day and natural gas averaged 2.54 billion cubic feet per day.

The company’s record sales volumes were highlighted by an increase of approximately 20,000 barrels of oil per day (BOPD) over the first quarter of 2012. This growth was driven by the Wattenberg HZ (horizontal) program in northeast Colorado, Caesar/Tonga in the deepwater Gulf of Mexico and increased volumes resulting from the Algeria tax resolution. In Wattenberg, net sales volumes averaged approximately 85,000 BOE per day during the quarter. The company is currently producing from about 75 horizontal wells in the Wattenberg field that are delivering excellent results and rates of return exceeding 100 percent in the current price environment. Anadarko is currently running seven horizontal rigs in the play with plans to increase to 10 rigs over the next few months. The company also benefited from the first full quarter of production at Caesar/Tonga, which averaged approximately 40,000 BOPD gross from three wells. Anadarko plans to spud a fourth well in the development during the third quarter of 2012. In addition, the Eagleford Shale, East Texas HZ, Greater Natural Buttes and Marcellus Shale each achieved record sales volumes during the quarter.

EXPLORATION SUMMARY

Anadarko continued an active and successful exploration and appraisal program during the second quarter of 2012. Offshore Mozambique, the company extended its exploration success beyond the Prosperidade complex with the discoveries of Golfinho and Atum, forming the company’s second major natural gas complex. The Golfinho/Atum complex is estimated to hold 10 to 30-plus trillion cubic feet of recoverable natural gas resources and is completely contained within the Offshore Area 1 block. Anadarko has begun an accelerated four-well appraisal program at Golfinho/Atum, with the first appraisal well encountering 254 net feet of natural gas pay. Significant progress was also made during the quarter at the company’s Prosperidade complex, where the appraisal drilling program was successfully completed, and well testing is ongoing.

In West Africa, Anadarko announced its first significant discovery offshore Côte d’Ivoire with the successful Paon exploration well in the CI-103 block during the quarter. The well encountered more than 100 net feet of light oil pay in Turonian-aged sands and confirmed the Upper Cretaceous fan system present in Ghana extends westward into Côte d’Ivoire. In July, the company announced that the successful Wawa exploration well, located in the Deepwater Tano Block offshore Ghana, encountered

3

approximately 108 net feet of oil and gas-condensate pay. Data indicate the Wawa discovery is a separate and distinct accumulation north of the TEN (Tweneboa, Enyenra and Ntomme) complex, and it extends the presence of hydrocarbon-bearing formations more than six miles north of the Enyenra-3A well. Within the TEN complex, the partnership’s active appraisal program continued with a successful drillstem test at the Ntomme discovery. The well flowed at facility-constrained rates of more than 20,000 BOPD from two zones. These results provide additional confidence in advancing the TEN complex toward a Plan of Development, which is expected to be submitted to the Ghanaian government in the next few months.

In the Gulf of Mexico, Anadarko announced a successful sidetrack appraisal well at the Heidelberg field in the Green Canyon area, advancing the project closer to sanction, which is expected in early 2013. In the Mississippi Canyon area, the third successful appraisal well of the Vito discovery encountered approximately 620 net feet of oil pay, leading the partnership to significantly increase Vito’s estimated recoverable resources to more than 300 million BOE from the previous estimate of more than 200 million BOE.

Early in the second quarter, Anadarko closed the $400 million joint-venture agreement for future development costs at its Salt Creek Enhanced Oil Recovery field in Wyoming. Later in the quarter, the company signed a definitive agreement to enter into a joint venture for the Lucius development in the deepwater Gulf of Mexico. Under the terms of the definitive agreement, Anadarko will be carried for $556 million, which is estimated to represent 100 percent of its expected capital obligation at Lucius through first production. In exchange, Anadarko will convey a 7.2-percent working interest in the Lucius development and will continue as operator with a 27.8-percent working interest. The transaction is expected to close during the third quarter and is subject to customary closing conditions.

OPERATIONS REPORT

For more details on Anadarko’s operations and exploration results, please refer to the comprehensive report on second-quarter 2012 activity. The report is available at www.anadarko.com on the Investor Relations page.

FINANCIAL SUMMARY

Anadarko ended the second quarter of 2012 with approximately $2.8 billion of cash on hand and generated approximately $142 million of free cash flow,⁽²⁾ which includes the impact of $123 million of capital expenditures incurred by Western Gas Partners, LP (NYSE: WES). In addition to the free cash flow, Anadarko received approximately $113 million associated with the Algeria tax resolution,

4

representing the first collection of an expected recoupment of approximately $1 billion during 2012. The company also reduced the outstanding balance of its revolving credit facility by approximately $800 million during the quarter, lowering its net debt⁽²⁾ to approximately $12 billion and its net debt to adjusted capital ratio⁽²⁾ to less than 38 percent.

As described in the items affecting comparability on page six of the release, the company recorded a non-cash charge of $978 million primarily related to the impairment of coalbed methane properties as a result of low natural gas prices.

TRONOX

The company continues to seek a reasonable resolution of the Tronox Adversary Proceeding (the Proceeding), although the parties have not reached a mutually acceptable agreement as of the date of this release. Anadarko’s second-quarter results included in this release are preliminary and do not reflect any updates to the financial reserve and associated taxes related to the Proceeding. The company’s second-quarter Form 10-Q, to be filed on or before Aug. 9, 2012, will include updated disclosure regarding the Proceeding and any adjustments to these financial statements as appropriate.

CONFERENCE CALL TOMORROW AT 9 A.M. CDT, 10 A.M. EDT

Anadarko will host a conference call on Tuesday, July 31, at 9 a.m. Central Daylight Time (10 a.m. Eastern Daylight Time) to discuss second-quarter results, current operations and the company’s outlook for the remainder of 2012. The dial-in number is 855.812.0464 in the United States, or 970.300.2271 internationally. The confirmation number is 98298659. 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

5

health and welfare. As of year-end 2011, the company had approximately 2.54 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 visit www.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, to meet financial and operating guidance, to consummate the transactions identified in this news release, and to successfully plan, build and operate an LNG project. See “Risk Factors” in the company’s 2011 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.

Cautionary Note to U.S. Investors: Effective Jan. 1, 2010, the United States Securities and Exchange Commission (“SEC”) permits oil and gas companies, in their filings with the SEC, to disclose only proved, probable and possible reserves that meet the SEC’s definitions for such terms. Anadarko uses certain terms in this news release, such as “recoverable natural gas resources,” “estimated recoverable resources” and similar terms that the SEC’s guidelines strictly prohibit Anadarko from including in filings with the SEC. U.S. investors are urged to consider closely the disclosure in Anadarko’s Form 10-K for the year ended Dec. 31, 2011, File No. 001-08968, available from Anadarko at www.anadarko.com or by writing Anadarko at: Anadarko Petroleum Corporation, 1201 Lake Robbins Drive, The Woodlands, Texas 77380, Attn: Investor Relations. This form may also be obtained by contacting the SEC at 1-800-SEC-0330.

#        #        #

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

Wayne Rodrigs, wayne.rodrigs@anadarko.com, 832.636.2305

6

Anadarko Petroleum Corporation

Certain Items Affecting Comparability

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.

7

Anadarko Petroleum Corporation

Reconciliation of GAAP to Non-GAAP Measures

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.

8

Anadarko Petroleum Corporation

(Unaudited)

9

Anadarko Petroleum Corporation

(Unaudited)

10

Anadarko Petroleum Corporation

(Unaudited)