CNOOC Limited New Discovery Luda 21-2 in Bohai

LD 21-2 is located in the inverted structure belt of LD 22-27 in south Liaodong Bay, with its south part adjacent to LD 27-2 oilfield. The average water depth is 20 meters. The discovery well of LD 21-2-1D is drilled and completed at a depth of 2,831 meters and encountered oil pay zones with total thickness of about 170 meters, representing the thickest oil layers found in the exploration of Bohai clastic rocks in recent years. Currently, oil production of the well is tested at around 608 barrels per day.

Mr. Zhu Weilin, Executive Vice President of the Company and General Manager of Exploration Department commented, "The discovery of LD21-2 not only has fairly good economics in exploration and development, but also further confirms high quality oil and gas accumulation of the inverted structure belt of LD 22-27 as well as good prospects for future exploration."

Notes to Editors:

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

This press release includes "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995, including statements regarding expected future events, business prospectus or financial results. The words "believe", "intend", "expect", "anticipate", "project", "estimate", "plan", "predict" and similar expressions are intended to identify such forward-looking statements. These statements are based on assumptions and analysis made by the Company in light of its experience and perception of historical trends, current conditions and expected future developments, as well as other factors that the Company believes reasonable under the circumstances. However, whether actual results and developments will meet the Company's expectations and predictions depends on a number of risks and uncertainties which could cause the actual results, performance and financial conditions to differ materially from the Company's expectations, including those associated with fluctuations in crude oil and natural gas prices, the exploration or development activities, the capital expenditure requirements, the business strategy, the highly competitive nature of the oil and natural gas industries, the foreign operations, environmental liabilities and compliance requirements, and economic and political conditions in the People's Republic of China. For a description of these and other risks and uncertainties, please see the documents the Company has filed from time to time with the United States Securities and Exchange Commission, including 2011 Annual Report on Form 20-F filed on April 20, 2012.

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

For further enquiries, please contact:

Ms. Ding Jianchun
Manager, Media / Public Relations
CNOOC Limited
Tel: +86-10-8452-2973
Fax: +86-10-8452-1441
E-mail: dingjch@cnooc.com.cn

Ms. Zhang Yuxiao
Senior Supervisor, Media/Public Relations
CNOOC Limited
Tel: +86-10-8452-6642
Fax: +86-10-8452-1441
E-mail: zhangyx12@cnooc.com.cn

Ms. Angela Hui
Ketchum Newscan Public Relations Ltd
Tel: +852-3141-8091
Fax: +852-2510-8199
E-mail: angela.hui@knprhk.com