(Hong Kong, September 1, 2022) CNOOC Limited (the “Company”, SEHK: 00883, SSE: 600938) announced today that Dongfang 1-1 Gas Field Southeast Zone and Ledong 22-1 Gas Field South Block Development Project commenced production ahead of schedule.

The development projects locate in Yinggehai, Western South China Sea, with an average water depth of 90 meters. Utilizing the existing processing facilities of Dongfang 1-1 platform and Ledong 22-1 platform, the projects plan to commission 4 development wells and to produce through 2 subsea production systems, 2 mixed transportation pipelines of oil and gas and 2 umbilicals. The projects are expected to reach their peak production of approximately 44 million cubic feet of natural gas per day.

CNOOC Limited holds 100% interest in Dongfang 1-1 Gas Field Southeast Zone and Ledong 22-1 Gas Field South Block Development Project.

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Notes to Editors:

More information about the Company is available at http://www.cnoocltd.com.

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This press release includes forward looking information, including statements regarding the likely future developments in the business of the Company and its subsidiaries, such as expected future events, business prospects or financial results. The words “expect”, “anticipate”, “continue”, “estimate”, “objective”, “ongoing”, “may”, “will”, “project”, “should”, “believe”, “plans”, “intends” and similar expressions are intended to identify such forward-looking statements. These statements are based on assumptions and analyses made by the Company as of this date in light of its experience and its perception of historical trends, current conditions and expected future developments, as well as other factors that the Company currently believes are appropriate under the circumstances. However, whether actual results and developments will meet the current expectations and predictions of the Company is uncertain. Actual results, performance and financial condition may differ materially from the Company’s expectations, including but not limited to those associated with macro-political and economic factors, fluctuations in crude oil and natural gas prices, the highly competitive nature of the oil and natural gas industry, climate change and environment policies, the Company’s price forecast, mergers, acquisitions and divestments activities, HSSE and insurance policies and changes in anti-corruption, anti-fraud, anti-money laundering and corporate governance laws.

Consequently, all of the forward-looking statements made in this presentation are qualified by these cautionary statements. The Company cannot assure that the results or developments anticipated will be realised or, even if substantially realised, that they will have the expected effect on the Company, its business or operations.

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For further enquiries, please contact:

Ms. Ariel Wang Media & Public Relations CNOOC Limited Tel: +86-10-8452-6832 Fax: +86-10-8452-1441 E-mail: mr@cnooc.com.cn

Mr. Bunny Lee Porda Havas International Finance Communications Group Tel: +852 3150 6707 Fax: +852 3150 6728 E-mail: cnooc.hk@pordahavas.com