[citation needed] The CNOOC Group focuses on the exploitation, exploration and development of crude oil and natural gas in offshore China, along with its subsidiary COOEC.

[2] When the State Council implemented the regulation of the people's petroleum resources in cooperation with foreign enterprises on January 30, 1982, CNOOC was incorporated and authorized to assume overall responsibility for the exploitation of oil and gas resources of offshore China in cooperation with foreign partners, which ensured monopoly status for CNOOC in offshore oil and natural gas.

[6][7] Despite a hands-off approach from the Bush administration, a group of Democrats and Republicans in Congress organized opposition to the CNOOC Limited bid.

They argued that with $13 billion of CNOOC Limited's bid for Unocal coming from the Chinese government, the offer was not a free market transaction.

In accordance with the commitment by the Chinese government to join the World Trade Organization, the oil market will be opened to non-Chinese companies (such as ExxonMobil and BP) by the end of 2006.

[16] On June 5, 2018, CNOOC Gas and Power Group Co. Ltd., a subsidiary of China National Offshore Oil Corporation (CNOOC), China's largest LNG importer and terminal operator, has recently signed a memorandum of understanding (MOU) with the Philippine fuel retailer Phoenix Petroleum to study, plan, and develop a liquefied natural gas (LNG) receiving terminal project in the Philippines.

[21] In May 2023, CNOOC reported that a demonstration project of a deep-sea floating wind farm «Haiyou Guanlan», located near the Wenchang oil fields in the west of the South China Sea, 136 kilometers from the shore and 120 meters deep, fed electricity into the grid.

Domestic production was 24.72 million tons, an 11-percent increase from the previous year and higher than the average national growth rate of three percent.

In these projects, CNOOC is responsible for constructing LNG receiving terminals and trunk lines for gas transmission and gas-fired power plants.

CNOOC Engineering's share price on the Shanghai Stock Exchange rose by 66.11 percent, and the market capitalization of China Oilfield Services reached RMB10.1 billion.

[citation needed] Under ex-CEO Wei Liucheng (who was promoted to the governor of Hainan province in October 2003) and chairman and chief executive Fu Chengyu (傅成玉), CNOOC undertook a number of mergers and acquisitions.

CNOOC tried to acquire 12.5 percent of Australia's Gorgon field to ensure supply to the Shanghai and Zhejiang LNG projects, but the parties could not agree on a price.

[citation needed] According to SASAC, in December 2008 CNOOC made a light oil and gas discovery in the 100-million-ton class at its Jinzhou 25-1 field in Bohai Bay.

[27]: 165  In Uganda, CNOOC has partnered with Total and Tullow Oil to develop the Lake Albert basin deposit, where CNOCC is also the operator.

[27]: 165 In October 2004, contract-sharing was negotiated in Burma by Myanmar Oil and Gas Enterprise, China Huanqiu Contracting and Engineering Corporation and CNOOC's Singaporean joint-venture partner, Golden Aaron.

Ten workers from Kyaukphyu were detained and questioned by authorities after a dispute with CNOOC over low wages, long hours,[28] reported underpayment and the mistreatment of inhabitants.

Arakan Oil Watch stated in a report that the company "left behind such a trail of abuses and environmental contamination on Ramree Island that outraged locals attacked their facilities".

[30] CNOOC's actions in Burma have been compared to that of communist officials in rural China, where entrepreneurs desiring development opposed by local residents steamroll their opposition.

[39] In December 2020, the United States Department of Defense named CNOOC as a company "owned or controlled" by the People's Liberation Army and thereby prohibited from receiving any American investment.