CNOOC Limited (the “Company” or “CNOOC Limited”, together with its subsidiaries, the “Group” or “we”), incorporated in the Hong Kong Special Administration Region (“Hong Kong”) in August 1999, was listed on the New York Stock Exchange (“NYSE”) (code: CEO) and The Stock Exchange of Hong Kong Limited (code: 00883) on 27 and 28 February 2001, respectively. The Company was admitted as a constituent stock of the Hang Seng Index in July 2001. The Company was listed on the Toronto Stock Exchange (code: CNU) on 18 September 2013. On 26 February 2021, NYSE announced to commence delisting proceedings of American Depositary Shares (“ADSs”) of the Company. On 10 March 2021, the Company requested for review of NYSE’s determination.

The Group is the largest producer of offshore crude oil and natural gas in China and one of the largest independent oil and gas exploration and production companies in the world. The Group mainly engages in exploration, development, production and sale of crude oil and natural gas.

The Group’s core operation areas are Bohai, the Western South China Sea, the Eastern South China Sea and the East China Sea in offshore China. The Group has oil and gas assets in Asia, Africa, North America, South America, Oceania and Europe.

As of 31 December 2020, the Group owned net proved reserves of approximately 5.37 billion BOE, and its average daily net production was 1,443,201 BOE (unless otherwise stated, all amounts of reserve and production in this annual report include reserve and production accounted for by equity method). The Group had total assets of approximately RMB721.3 billion.