Anadarko Petroleum
A former U.S. independent oil and gas exploration and production company acquired by Occidental Petroleum in 2019.
Last updated August 31, 2026
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Overview
Anadarko Petroleum Corporation was a U.S.-based independent energy company focused primarily on hydrocarbon exploration, field development, production, and related midstream activities. It was formed in 1959 as a subsidiary of Panhandle Eastern Corporation Pipe Line Company after major natural-gas discoveries in the Anadarko Basin, a geological region extending across parts of Oklahoma, Texas, Kansas, and Colorado. The company took its name from that basin and initially developed as an exploration and production business. Anadarko became an independent public company in 1986 when Panhandle Eastern distributed its interests in the business to shareholders through a spin-off. Over the following decades, it expanded through acquisitions and organic development. Important transactions included the purchase of Union Pacific Resources in 2000, Berkeley Petroleum Corporation in 2001, Western Gas Resources in 2006, and Kerr-McGee in 2006. These deals substantially broadened Anadarko's domestic and international asset base and increased its exposure to oil, natural gas, gathering, processing, treating, transportation, and mineral interests. By the end of 2018, Anadarko's portfolio included major U.S. positions in the Delaware Basin, the Denver Basin, Greater Natural Buttes in Utah, and the Gulf of Mexico. It also held international interests in Algeria, Ghana, Mozambique, Colombia, and Côte d'Ivoire. The company participated in both operated and non-operated projects, including offshore developments and joint ventures. Its resource mix included crude oil, natural gas, and natural gas liquids. The company reported approximately 1.473 billion barrels of oil equivalent in proved reserves at December 31, 2018, with oil representing 45 percent, natural gas 37 percent, and natural gas liquids 18 percent. U.S. activities accounted for most of its sales volumes and proved reserves. Anadarko also became associated with significant environmental and legal liabilities. Its acquisition of Kerr-McGee resulted in successor liability for environmental contamination connected with the former Tronox subsidiary. In 2014, Anadarko agreed to a $5.15 billion settlement with the U.S. Department of Justice and Environmental Protection Agency concerning waste sites across the United States. The settlement was described at the time as the largest environmental contamination settlement in U.S. history. Anadarko also held a 25 percent non-operating interest in the Macondo prospect involved in the 2010 Deepwater Horizon disaster. It settled related claims with BP in 2011 and later faced a civil penalty under the Clean Water Act. In 2019, Anadarko became the target of competing acquisition interest from Occidental Petroleum and Chevron. Occidental ultimately prevailed, completing its acquisition of Anadarko in August 2019. Anadarko consequently ceased to exist as an independent public company, and its assets and operations were integrated into Occidental's portfolio.
History
Anadarko Petroleum originated in 1959 as a subsidiary of Panhandle Eastern Corporation Pipe Line Company. Its formation followed the discovery of substantial natural-gas resources in the Anadarko Basin, which extends across western Oklahoma, the Texas Panhandle, southwestern Kansas, and southeastern Colorado. The new business was organized to pursue exploration and production opportunities in and around that basin. In 1986, Panhandle Eastern distributed its interest in Anadarko to shareholders through a corporate spin-off. Anadarko thereby became a publicly traded independent company. It later developed a broader domestic portfolio and expanded internationally through acquisitions, asset purchases, and joint ventures. Its acquisition of Union Pacific Resources in April 2000 strengthened its U.S. exploration and production position. In June 2001, Anadarko acquired Berkeley Petroleum Corporation, assuming additional debt as part of the transaction. The company underwent a leadership transition in December 2003, when Robert J. Allison Jr. resigned as chief executive and James T. Hackett, previously associated with Devon Energy, became CEO. Anadarko continued its expansion in 2006 by acquiring Western Gas Resources for cash and purchasing Kerr-McGee for $16 billion. The Kerr-McGee transaction created substantial environmental successor liabilities because of the historical activities connected with Kerr-McGee's former Tronox subsidiary. Anadarko subsequently sold various non-core assets, including West Texas properties in 2007, Oklahoma and Texas properties in 2007, and its interest in Brazil's Peregrino heavy-oil field in 2008. Anadarko invested in its corporate headquarters in The Woodlands, Texas. It purchased a 7.5-acre site in 1999 for a planned 800,000-square-foot, 32-story headquarters tower. A second adjacent tower began construction in 2012, and both buildings were completed in 2014. The towers were named Allison Tower and Hackett Tower after former chief executives. In 2011, Anadarko resolved its dispute with BP concerning the Macondo prospect and the Deepwater Horizon disaster. Anadarko had owned a 25 percent non-operating interest in the prospect, which BP operated. The settlement transferred Anadarko's interest to BP and provided indemnification for spill-related costs in exchange for a $4 billion payment. A later federal ruling imposed a $159.5 million Clean Water Act civil penalty based on the ownership interest, despite the court's conclusion that Anadarko was not culpable for causing the accident. The company continued to reshape its portfolio in the 2010s. In 2012 it sold midstream assets to Western Gas Partners and announced the Collier gas-field discovery offshore Mozambique. A planned executive succession saw Al Walker become CEO in 2012; Hackett served as executive chairman until retiring in 2013, when Walker also became chairman. Anadarko explored a 2015 acquisition of Apache Corporation, but Apache rejected the offer. During 2016 and 2017, Anadarko sold or divested selected gathering, Marcellus, Eagle Ford, and other assets while acquiring Gulf of Mexico properties from Freeport-McMoRan. Environmental litigation remained a defining part of the company's later history. In 2014, Anadarko reached a $5.15 billion settlement with the U.S. Department of Justice and Environmental Protection Agency over contamination at sites associated with Kerr-McGee and Tronox. The settlement covered waste and pollution across numerous states and was described at the time as the largest environmental contamination settlement in American history. By 2018, Anadarko's main business was concentrated in U.S. onshore basins, the Gulf of Mexico, and selected international projects. Its international portfolio included Algeria, Ghana, Mozambique, Colombia, and Côte d'Ivoire. In 2019, Occidental Petroleum made a successful acquisition proposal after competing with Chevron. Occidental completed the transaction in August 2019, after which Anadarko ceased operating as an independent public company and its assets were incorporated into Occidental.
- 2019
Acquisition by Occidental Petroleum
[1]Occidental completed its acquisition of Anadarko after outbidding Chevron, ending the company's independent corporate existence.
- 2014
Tronox environmental settlement
[1]Anadarko agreed to a $5.15 billion settlement concerning environmental contamination linked to Kerr-McGee and Tronox.
- 2011
Macondo settlement with BP
[1]Anadarko settled claims related to Deepwater Horizon for $4 billion and transferred its Macondo interest to BP.
- 2006
Western Gas Resources and Kerr-McGee acquisitions
[1]Anadarko acquired Western Gas Resources and Kerr-McGee, materially enlarging its production portfolio and creating later environmental successor liabilities.
- 2001
Berkeley Petroleum acquisition
[1]The company acquired Berkeley Petroleum Corporation for C$1.2 billion and assumed C$400 million of debt.
- 2000
Union Pacific Resources acquisition
[1]Anadarko acquired Union Pacific Resources in a transaction valued at $4.4 billion.
- 1986
Spin-off into a public company
[1]Panhandle Eastern distributed its interest in Anadarko to shareholders, making Anadarko an independent public company.
- 1959
Formation in the Anadarko Basin
[1]Anadarko was formed as a Panhandle Eastern subsidiary after major natural-gas discoveries in the Anadarko Basin.
Products and positioning
Independent upstream oil and gas exploration and production company with domestic unconventional, Gulf of Mexico, and international LNG and offshore assets.
Energy commodity
Crude oil
Crude oil was a principal output of Anadarko's exploration and production portfolio. Production came from U.S. onshore properties, Gulf of Mexico interests, and selected international projects. Oil was also the largest component of the company's proved-reserve mix at the end of 2018.
Energy commodity
Natural gas
Natural gas was a core Anadarko product, originating from domestic basins and international developments such as Mozambique's offshore gas resources. The company explored for, developed, produced, gathered, processed, treated, and transported gas through operated assets and joint ventures.
Energy commodity
Natural gas liquids
Natural gas liquids were associated hydrocarbon products recovered from Anadarko's gas-producing operations. They formed part of the company's reserve and production portfolio alongside crude oil and dry natural gas.
LNG development · 2019
Mozambique LNG
Mozambique LNG was a joint-venture development based on the Golfinho and Atum gas fields in Offshore Area 1. Anadarko and its co-venturers began the project in 2019 to support Mozambique's first onshore LNG development.
Controversies
2014
Tronox environmental contamination litigation
As Kerr-McGee's successor, Anadarko faced claims concerning extensive historical contamination associated with Kerr-McGee and its former Tronox subsidiary. The matter covered waste sites in numerous states, including radioactive waste, industrial pollution, and other hazardous contamination. Anadarko agreed to a $5.15 billion settlement with the U.S. Department of Justice and Environmental Protection Agency.
2010
Deepwater Horizon and Macondo liability
Anadarko owned a 25 percent non-operating interest in the Macondo prospect, operated by BP, when the Deepwater Horizon explosion and oil spill occurred. Anadarko disputed responsibility and argued that BP's gross negligence or willful misconduct triggered the disaster. It nevertheless faced cleanup and statutory liabilities associated with its ownership interest.
2009
Tronox shareholder lawsuit
Tronox shareholders sued Anadarko as Kerr-McGee's successor, alleging that investors had been misled about the environmental and other liabilities transferred to Tronox.
Brand decisions
2019
Accept Occidental Petroleum acquisitionM&ABackground
Anadarko became the subject of competing acquisition interest from Occidental Petroleum and Chevron.
Action taken
Occidental outbid Chevron and completed the acquisition of Anadarko in August 2019.
Aftermath
Anadarko ceased to operate as an independent public company and its assets were integrated into Occidental Petroleum.
- Chevron Corporation — Chevron made a competing proposal but was outbid by Occidental Petroleum.
2015
Attempted acquisition of ApacheM&ABackground
Anadarko made an offer to acquire Apache Corporation as part of its broader portfolio strategy.
Action taken
Anadarko submitted an acquisition proposal, which Apache rejected.
Aftermath
The proposed transaction did not proceed.
2011
Settle Macondo claims with BPOtherBackground
Anadarko held a 25 percent non-operating interest in BP-operated Macondo, the prospect involved in the Deepwater Horizon disaster.
Action taken
Anadarko paid $4 billion, transferred its Macondo interest to BP, and received indemnification for spill-related costs.
Aftermath
The settlement ended Anadarko's direct ownership of Macondo, although the company later faced a Clean Water Act civil penalty tied to its ownership interest.
Settlement payment. $4 billion (2011)
2006
Acquire Kerr-McGeeM&ABackground
Anadarko sought to expand its exploration and production portfolio through a major acquisition.
Action taken
It acquired Kerr-McGee for $16 billion in cash.
Aftermath
The transaction expanded Anadarko's assets but also exposed it to substantial environmental successor liabilities related to Kerr-McGee's historical operations.
Transaction value. $16 billion (2006)
Recent events
- Unconfirmed
Total completes acquisition of Anadarko’s Mozambique LNG stake[2]
Total completed its acquisition of a 26.5% stake held by Anadarko Petroleum in the Mozambique LNG project for $3.9 billion.
Sources2 sources
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