News Release

A Mid-sized Discovery Liuhua 20-2 Made in Eastern South China Sea

HONG KONG, May 27, 2015 /PRNewswire/ -- CNOOC Limited (the "Company", NYSE: CEO, SEHK: 00883, TSX: CNU) announced that the Company made a mid-sized discovery Liuhua 20-2 in the Eastern South China Sea.

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The Liuhua 20-2 structure is located in Northern Slope Belt of Baiyun Sag in the Pearl River Mouth Basin of the South China Sea with an average water depth of about 390 meters. The discovery well LH20-2-1 was drilled and completed at a depth of about 2,970 meters and encountered oil pay zones with a total thickness of 35.2 meters. The oil production of the well tested around 8,000 barrels per day and the crude oil density is approximately 0.75.

The successful exploration of Liuhua 20-2 has further proved the huge exploration potential of Baiyun Sag in the Pearl River Mouth Basin, and Baiyun Sag is expected to become the new reserves growth area of deepwater exploration of crude oil in South China Sea.

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 "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 in light of its experience and its perception of historical trends, current conditions and expected future developments, as well as other factors the Company believes are appropriate under the circumstances. However, whether actual results and developments will meet the expectations and predictions of the Company depends on a number of risks and uncertainties which could cause the actual results, performance and financial condition to differ materially from the Company's expectations, including but not limited to those associated with fluctuations in crude oil and natural gas prices, the exploration or development activities, the capital expenditure requirements, the business strategy, whether the transactions entered into by the Group can complete on schedule pursuant to their terms and timetable or at all, 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 files from time to time with the United States Securities and Exchange Commission, including the 2014 Annual Report on Form 20-F filed on 22 April 2015.

Consequently, all of the forward-looking statements made in this press release 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.

For further enquiries, please contact:

Ms. Michelle Zhang
Deputy Manager, Media / Public Relations
CNOOC Limited
Tel: +86-10-8452-6642
Fax: +86-10-8452-1441
E-mail: MR@cnooc.com.cn

Ms. Cathy Zhang
Hill+Knowlton Strategies Asia
Tel: +852-2894-6211
Fax: +852-2576-1990
E-mail: cathy.zhang@hkstrategies.com  

SOURCE CNOOC Limited