CNOOC : PROPOSED NOTES ISSUE TO BE GUARANTEED BY THE COMPANY

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

This announcement is not an offer to sell or a solicitation of any offer to buy the securities of CNOOC Limited (the "Company") or any of its subsidiaries (the "Securities") in the United States or in any other jurisdiction. Securities may not be offered or sold in the United States absent registration or an exemption from registration under the U.S. Securities Act of 1933. Any public offering of the Company's securities to be made in the United States will be made by means of a prospectus that may be obtained from the Company and that will contain detailed information about the Company and management, as well as financial statements. The Company intends to conduct a public offering of the securities as described herein in the United States pursuant to the Company's post-effective amendment No. 1 to the shelf registration statement on Form F-3 (File No.333-224357) filed with the United States Securities and Exchange Commission on 20 September 2019.

No PRIIPs key information document (KID) has been prepared as not available to retail in EEA.

(Incorporated in Hong Kong with limited liability under the Companies Ordinance)

(Stock Code: 00883)

PROPOSED NOTES ISSUE

TO BE GUARANTEED BY THE COMPANY

This announcement is made by the Company pursuant to the Inside Information Provision under Part XIVA of the Securities and Futures Ordinance (Chapter 571 of the laws of Hong Kong) and Rule 13.09 of the Listing Rules.

CNOOC Finance (2013), a wholly-owned subsidiary of the Company, proposes to offer the Notes to professional investors in Hong Kong and elsewhere outside the United States, and in the United States pursuant to the Company's post-effective amendment No. 1 to the shelf registration statement on Form F-3 (File No. 333-224357) filed with the SEC on 20 September 2019. The Notes are expected to be issued by CNOOC Finance (2013) and guaranteed by the Company. The completion of the Proposed Notes Issue is subject to market conditions and investors' interest. Bank of China Limited, BOCI Asia Limited, Citigroup Global Markets Inc., Goldman Sachs (Asia) L.L.C., J.P. Morgan Securities LLC and UBS AG Hong Kong Branch, as the joint global coordinators, joint lead managers and joint bookrunners and ABCI Capital Limited, Agricultural Bank of China Limited Hong Kong Branch, The Bank of East Asia, Limited, BOCOM International Securities Limited, China International Capital Corporation Hong Kong Securities Limited, ICBC International Securities Limited and Société Générale as the joint bookrunners, are managing the Proposed Notes Issue.

1

If the Notes are issued, the proceeds of the Proposed Notes Issue are intended to be used for general corporate purposes.

Application has been made to the Hong Kong Stock Exchange for listing of, and permission to deal in, the Notes by way of debt issue to professional investors only. Listing of the Notes on the Hong Kong Stock Exchange is not to be taken as an indication of the merits of the Notes, the Company or CNOOC Finance (2013).

As no binding agreement in relation to the Proposed Notes Issue has been entered into as at the date of this announcement, the Proposed Notes Issue may or may not materialise. The completion of the Proposed Notes Issue is subject to market conditions and investors' interest. Investors and shareholders of the Company are urged to exercise caution when dealing in the securities of the Company.

Further announcements in respect of the Proposed Notes Issue will be made by the Company should the underwriting agreement in respect of the Proposed Notes Issue be signed or as and when necessary.

This announcement is made by the Company pursuant to the Inside Information Provision under Part XIVA of the Securities and Futures Ordinance (Chapter 571 of the laws of Hong Kong) and Rule 13.09 of the Listing Rules.

THE PROPOSED NOTES ISSUE

Introduction

CNOOC Finance (2013), a wholly-owned subsidiary of the Company, proposes to offer the Notes to professional investors in Hong Kong and elsewhere outside the United States, and in the United States pursuant to the Company's post-effective amendment No. 1 to the shelf registration statement on Form F-3 (File No. 333-224357) filed with the SEC on 20 September 2019. The Notes are expected to be issued by CNOOC Finance (2013) and guaranteed by the Company. The completion of the Proposed Notes Issue is subject to market conditions and investors' interest. Bank of China Limited, BOCI Asia Limited, Citigroup Global Markets Inc., Goldman Sachs (Asia) L.L.C., J.P. Morgan Securities LLC and UBS AG Hong Kong Branch, as the joint global coordinators, joint lead managers and joint bookrunners and ABCI Capital Limited, Agricultural Bank of China Limited Hong Kong Branch, The Bank of East Asia, Limited, BOCOM International Securities Limited, China International Capital Corporation Hong Kong Securities Limited, ICBC International Securities Limited and Société Générale as the joint bookrunners, are managing the Proposed Notes Issue.

Reason for the Proposed Notes Issue

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.

2

If the Notes are issued, the proceeds of the Proposed Notes Issue are intended to be used for general corporate purposes.

Listing

Application has been made to the Hong Kong Stock Exchange for listing of, and permission to deal in, the Notes by way of debt issue to professional investors only. Listing of the Notes on the Hong Kong Stock Exchange is not to be taken as an indication of the merits of the Notes, the Company or CNOOC Finance (2013).

GENERAL

As no binding agreement in relation to the Proposed Notes Issue has been entered into as at the date of this announcement, the Proposed Notes Issue may or may not materialise. The completion of the Proposed Notes Issue is subject to market conditions and investors' interest. Investors and shareholders of the Company are urged to exercise caution when dealing in the securities of the Company.

Further announcements in respect of the Proposed Notes Issue will be made by the Company should the underwriting agreement in respect of the Proposed Notes Issue be signed or as and when necessary.

DEFINITIONS

In this announcement, unless the context requires otherwise, the following expressions have the following meanings:

"Board"	the board of Directors
"CNOOC Finance (2013)"	CNOOC Finance (2013) Limited, a business company
	incorporated with limited liability in the British Virgin
	Islands under the BVI Business Companies Act 2004 (as
	amended), and a wholly-owned subsidiary of the Company
"Company"	CNOOC Limited, a company incorporated in Hong Kong
	with limited liability, whose shares are listed on the Hong
	Kong Stock Exchange and whose American Depositary
	Receipts are listed on the New York Stock Exchange and
	the Toronto Stock Exchange
"Director(s)"	the directors of the Company
"Group"	the Company and its subsidiaries from time to time
"Hong Kong"	the Hong Kong Special Administrative Region of the PRC
"Hong Kong Stock Exchange"	The Stock Exchange of Hong Kong Limited

3

"Listing Rules"	the Rules Governing the Listing of Securities on the Hong
	Kong Stock Exchange
"Notes"	the senior notes expected to be issued by CNOOC Finance
	(2013) and guaranteed by the Company
"PRC"	the People's Republic of China excluding, for the purpose
	of this announcement, Hong Kong, the Macau Special
	Administrative Region and Taiwan
"Proposed Notes Issue"	the proposed issue of the Notes
"SEC"	the United States Securities and Exchange Commission
"U.S." or "United States"	the United States of America, its territories and possessions
	and all areas subject to its jurisdiction

By Order of the Board

CNOOC Limited

Wu Xiaonan

Joint Company Secretary

Hong Kong, 20 September 2019

As at the date of this announcement, the Board comprises:

Executive Director	Independent Non-executive Directors
Xu Keqiang	Chiu Sung Hong
	Lawrence J. Lau
Non-executive Director	Tse Hau Yin, Aloysius
Wang Dongjin (Vice Chairman)	Qiu Zhi Zhong

4