致登记持有人之通知信函及回条 – 以电子方式发布公司通讯之安排

(Incorporated in Hong Kong with limited liability under the Companies Ordinance) （根据公司条例于香港注册成立的有限公司） Stock Codes: 00883 (HKD Counter) and 80883 (RMB Counter) 股票代号：00883（港币柜台）及80883（人民币柜台） 28 June 2024 Dear registered holder(s) of the Hong Kong Shares (as defined below) Arrangement of Electronic Dissemination of Corporate Communications The English and Chinese versions of all Corporate Communications* of CNOOC Limited (the “Company”) are available electronically on the website of The Stock Exchange of Hong Kong Limited (the “Stock Exchange”) at www.hkexnews.hk and the Company's website at www.cnoocltd.com.The Company will supply Corporate Communications to holders of the shares of the Company listed on the The Stock Exchange of Hong Kong Limited (the “Hong KongShares”) by electronic means through the Stock Exchange's website at www.hkexnews.hk the Company's website at www.cnoocltd.com (the “Electronic Version”) provided that the relevant holders of Hong Kong Shares have consented to receiving the Electronic Version in accordance with the Rules Governing The Listing of Securities on The Stock Exchange of Hong Kong Limited the Companies Ordinance (Chapter 622 of the Laws of Hong Kong) and the Articles of Association of the Company.The Company is writing to seek your election regarding the means of receipt and the language of Corporate Communications of the Company to be published in the future: * If you elect to receive Electronic Version in the future please provide your email address by (i) scanning your personalized QR code printed on the enclosed reply form (the "Reply Form") or (ii) completing the Reply Form and returning it by post or by email to the Company’s Hong Kong share registrar (the “Share Registrar”) for the purposes of receiving (a) email notifications for publication of Corporate Communications on the Stock Exchange's website and the Company’s website and (b) Actionable Corporate Communications** in electronic form from the Company. However certain Actionable Corporate Communications because of their nature can only be sent in printed form. Registered holders of Hong Kong Shares should note that such documents will therefore be sent to their registered addresses by post even they may have provided email addresses to the Share Registrar.* If you elect to receive printed version of all Corporate Communications in the future please complete the enclosed Reply Form and return it by post or by email to the Share Registrar. Please note that such instruction shall be valid from the date on which such request form is received until the next time when the Company seeks consent from its registered holders of Hong Kong Shares to receiving the Electronic Version of all future Corporate Communications or until it is revoked or replaced or you cease to be a holder of Hong Kong Shares whichever is the earliest.If the Company does not receive a duly completed Reply Form or any response in writing indicating any objection from you by 26 July 2024 you are deemed to have elected the Electronic Version instead of printed version for all future Corporate Communications until you inform the Share Registrar otherwise. If you elect (or are deemed to have elected) the Electronic Version but do not provide a functional email address the Company will send to you by post at your address as it appears in the Company’s register of members (i) a notification letter for publication of Corporate Communications on the Stock Exchange's website and the Company’s website and (ii) Actionable Corporate Communications in printed form.Contact details of the Share Registrar: Postal address : 17M Floor Hopewell Centre 183 Queen’s Road East Wanchai Hong Kong Email address : cnooc.ecom@computershare.com.hk Should you have any queries relating to this letter please contact the Share Registrar at (852)2862 8688 during business hours from 9:00 a.m. to 6:00 p.m. (Hong Kong time) Mondays to Fridays excluding Hong Kong public holidays.Yours faithfully By order of the Board CNOOC Limited Mr. Xu Yugao Joint Company Secretary * "Corporate Communications" means any documents issued or to be issued by the Company for the information or action of holders of any of its securities including but not limited to (a) the directors’ report its annual accounts together with a copy of the auditors’ report and where applicable its summary financial report; (b) the interim report and where applicable its summary interim report; (c) a notice of meeting; (d) a listing document; (e) a circular; and (f) a proxy form.** "Actionable Corporate Communications" means any corporate communication that seeks instructions from the Company's securities holders on how they wish to exercise their rights or make an election as the Company's securities holder. For the avoidance of doubt Actionable Corporate Communications do not include notices of general meetings and proxy forms.(Incorporated in Hong Kong with limited liability under the Companies Ordinance)（根据公司条例于香港注册成立的有限公司） Stock Codes: 00883 (HKD Counter) and 80883 (RMB Counter) 股票代号：00883（港币柜台）及80883（人民币柜台） 各位香港股份（定义如下）登记持有人： 以电子方式发布公司通讯之安排 中国海洋石油有限公司（「本公司」）之所有公司通讯的英文版和中文版会在香港联合交易所有限公司（「联交所」）网站www.hkexnews.hk和本公司网站 www.cnoocltd.com 上提供。 本公司透过联交所网站www.hkexnews.hk 及本公司网站www.cnoocltd.com 以电子方式向本公司在香港联合交易所有限公司上市股份（「香港股份」）登记持有人提 供公司通讯*（「电子版本」），前提是根据香港联合交易所有限公司证券上市规则、公司条例（香港法例第622章）及本公司组织章程细则，相关香港股份持有人已同意收取电子版本。 本公司特此致函阁下就本公司日后刊发之公司通讯之收取方式及语言版本作出选择： *若阁下选择日后收取电子版本，请扫描回条上列印的阁下专属二维码，或填妥随附之回条并邮寄或电邮至本公司之香港股份过户处（「股份过户处」），提供阁下的电邮地址以便收取有关已在联交所网站及本公司网站上发布公司通讯的电邮通知，以及本公司以电子方式发布的可供采取行动的公司通讯**。然而，若干可供采取行动的公司通讯因其性质只能以印刷本形式发送，故香港股份持有人谨请注意，即使彼等已向本公司之香港股份过户处提供电邮地址，该等公司通讯仍将邮寄至彼等之登记地址。 *若阁下选择日后收取印刷本，请填妥随附之回条并邮寄或电邮至股份过户处。请注意该指示自收悉阁下指示之日起至本公司下一次向香港股份登记持有人寻求其同意以电子版本形式收取日后所有公司通讯之时有效，或直至该指示被撤回或取代或阁下不再是香港股份持有人为止（以较早者为准）。 若本公司于2024年7月26日之前尚无收到阁下已填妥之回条或表示反对之任何书面回复，阁下将被视作已选择日后收取所有公司通讯的电子版本（而非收取印刷本），直至阁下另行通知股份过户处为止。如阁下选择（或被视作选择）收取电子版本但没有提供有效的电邮地址，本公司将根据本公司股东名册所示的地址透过邮寄方式向阁下发送有关已在本公司网站及联交所网站上发布公司通讯的通知函件及可供采取行动的公司通讯的印刷本。 股份过户处联络资料 邮寄地址 : 香港湾仔皇后大道东 183 号合和中心 17M 楼 电邮地址 : cnooc.ecom@computershare.com.hk 如阁下对本函件有任何疑问，请于办公时间星期一至五（香港公众假期除外）上午9时正至下午6时正（香港时间）其间致电股份过户处(852)28628688查询。 承董事会命中国海洋石油有限公司联席公司秘书徐玉高谨启 * 「公司通讯」是指本公司发出或将予发出以供其任何证券的持有人参照或采取行动的任何文件，包括但不限于(a) 董事会报告、年度帐目以及核数师报告副本以及（如适用）财务摘要报告； (b) 中期报告及其中期报告摘要（如适用）； (c) 会议通知； (d) 上市文件； (e) 通函；和 (f) 代表委任表格。 **「可供采取行动的公司通讯」指任何涉及要求本公司的证券持有人指示其拟如何行使其证券持有人权利或作出选择的公司通讯。为免生疑问，可供采取行动的公司通讯不包括股东大会的通告及代表委任表格。 2024 年 6 月 28 日CCS9335 CNOH REPLY FORM 回条 To: Hong Kong Registrars Limited (The “Share Registrar”) 致： 香港证券登记有限公司 （「股份过户处」） 17M Floor Hopewell Centre 香港湾仔皇后大道东 183 号 183 Queen’s Road East Wanchai Hong Kong 合和中心 17M 楼 (Please choose ONLY ONE of the options below) (请从以下选项中只选择其中一项) Personalized QR Code Option 1: I/we hereby provide my email address for receipt of all future Corporate Communications* and 专属二维码 Actionable Corporate Communications** of the Company via electronic dissemination by scanning my personalized QR code. (Note 1) 选项1：本人/吾等现扫瞄本人/吾等的专属二维码提供本人/吾等之电子邮件地址，以接收公司通过电子方式发布附注 的所有未来公司通讯*及可供采取行动的公司通讯**。(1)Return of this Reply Form is NOT required if Option 1 is chosen.如选择了选项1，本回条无须交回。 Option 2 Option 2: I/we hereby provide my/our email address in writing for receipt of all future Corporate Communications* and Actionable Corporate Communications** of the Company via electronic dissemination. (Note 1) 选项2：本人/吾等现以书面提供本人/吾等之的电子邮件地址，以确保收到公司通过电子方式发布的未来公司通讯*及可供采取行动的公司通讯(附注1)**。 Name of registered holder(s) 登记股东姓名 : Name of the listed company 上市公司名称 : CNOOC Limited (the “Company”) 中国海洋石油有限公司（「公司」） (Please use ENGLISH BLOCK LETTERS 请用英文正楷填写) Email address 电邮地址: (Note 2 / 附注 2) Option 3: I/we hereby request for receipt of all future Corporate Communications* and Actionable Corporate Communications** in printed form. (Note 3) This instruction is valid only from the date on which such request form is received until the next time when the Company seeks consent from its registered holders of Hong Kong Shares to receiving the Electronic Version of all future Corporate Communications or until it is revoked or replaced or I/we cease to be a holder of Hong Kong Shares whichever is the earliest. (Please mark “?” in the below box if applicable) 选项3： Printed English version 英文印刷本 Printed Chinese version 中文印刷本 Printed English and Chinese versions 中、英文印刷本 (Notes 4 & 5) Signature(s): Contact number: Date: (附注4及5) 签名：联络电话号码：日期： (Please use ENGLISH BLOCK LETTERS 请用英文正楷填写) Notes 附注： 1. Certain Actionable Corporate Communications because of their nature can only be sent in printed form. Such documents will therefore be sent to your registered addresses by post even you may have provided email addresses. 若干可供采取行动的公司通讯因其性质只能以印刷本形式发送，即使彼等已提供电邮地址，该等公司通讯仍将邮寄至彼等之登记地址。 2. If you provide more than one email address by QR code email reply form and/or other means only the latest one email address provided will be registered. If the Company does not receive a functional email address you will receive a notification letter of the publication of the Corporate Communications* on the Stock Exchange's website and the Company’s website and the Actionable Corporate Communications** in printed form.如阁下通过二维码、电邮、回条及/或其他方式提供多于一个的电子邮件地址，阁下最后提供的电子邮件地址将会被用于登记。如公司没有收到阁下可用的电子邮件地址，阁下将收取有关公司通讯*已在联交所网站及公司网站登载的通知函印刷本，并且将收到可供采取行动的公司通讯**印刷本。 3. If you mark “?” in one of the boxes in Option 3 no email address will be registered and only Corporate Communications* and Actionable Corporate Communications** in printed form will be received. 如阁下在选项3其中一个空格方格内划上「?」号，将不会有电子邮件地址被登记，只有公司通讯*及可供采取行动的公司通讯**的印刷本会被收取。 4. Any Reply Form with no signature or otherwise incorrectly completed will be void. Please complete all your details clearly. If your shares are held in joint names all of the joint shareholders should jointly sign this Reply Form in order to be valid.任何回条若未有签署或在其他方面填写不正确，则将会作废。请清楚填妥阁下之所有资料。如属联名股东，则本回条须由所有联名股东联合签署，方为有效。 5. For the avoidance of doubt the Company does not accept any other instructions given on this Reply Form. 为免存疑，在本回条上的任何额外指示，公司将不予处理。 * "Corporate Communications" means any documents issued or to be issued by the Company for the information or action of holders of any of its securities including but not limited to (a) the directors’ report its annual accounts together with a copy of the auditors’ report and where applicable its summary financial report; (b) the interim report and where applicable its summary interim report; (c) a notice of meeting; (d) a listing document; (e) a circular and (f) a proxy form.「公司通讯」是指公司发出或将予发出以供其任何证券的持有人参照或采取行动的任何文件，包括但不限于(a) 董事会报告、年度帐目以及核数师报告副本以及（如适用）财务摘要报告； (b) 中期报告及其中期报告摘要（如适用）； (c) 会议通知； (d) 上市文件； (e) 通函；和 (f) 代表委任表格。 ** "Actionable Corporate Communications" means any corporate communication that seeks instructions from the Company's securities holders on how they wish to exercise their rights or make an election as the Company's securities holder. For the avoidance of doubt Actionable Corporate Communications do not include notices of general meetings and proxy forms.「可供采取行动的公司通讯」指任何涉及要求公司的证券持有人指示其拟如何行使其证券持有人权利或作出选择的公司通讯。为免生疑问，可供采取行动的公司通讯不包括股东大会的通告及代表委任表格。 PERSONAL INFORMATION COLLECTION STATEMENT收集个人资料声明 (i) “Personal Data” in this statement has the same meaning as “personal data” in the Personal Data (Privacy) Ordinance Chapter 486 of the Laws of Hong Kong (“ PDPO”).本声明中所指的「个人资料」与香港法例第486章《个人资料（私隐）条例》（「《私隐条例》」）中「个人资料」的涵义相同。 (ii) Your Personal Data provided in this Reply Form will be used in connection with including but not limited to the Company’s electronic dissemination of the Corporate Communications and to liaise with you on other matters relating to your holdings in the Company. Your supply of Personal Data to the Company is on a voluntary basis. In case of a failure to provide sufficient information the Company may not be able to process your instruction and/or request as stated in this Reply Form.阁下于本回条所提供的个人资料将用于(包括但不限于)有关公司以电子方式发布公司通讯文件及就阁下持有的公司证券有关的其他事宜上与阁下联络。阁下是自愿向公司提供个人资料。若阁下未能提供足够资料，公司可能无法处理阁下在本回条上所述的指示及/或要求。 (iii) Your Personal Data may be disclosed or transferred by the Company to its subsidiaries the Share Registrar and/or other companies or bodies for any of the stated purposes or when it is required to do so by law and will be retained for such period as may be necessary for our verification and record purposes.公司可就任何所说明的用途或在法例规定的情况下，将阁下的个人资料披露或转移给公司的附属公司、股份过户处、及/或其他公司或团体，并将在适当期间保留该等个人资料作核实及纪录用途。 (iv) You have the right to request access to and/or correction of your Personal Data in accordance with the provisions of the PDPO. Any such request for access to and/or correction of your Personal Data should be in writing by mail to the Hong Kong Privacy Officer of the Share Registrar at 17M Floor Hopewell Centre 183 Queen’s Road East Wanchai Hong Kong or by email at PrivacyOfficer@computershare.com.hk.阁下有权根据《私隐条例》的条文查阅及/或修改 阁下的个人资料。任何该等查阅及/或修改个人资料的要求均须以书面方式邮寄至股份过户处（地址为香港湾仔皇后大道东 183 号合和中心 17M 楼）向香港隐私主任提出，或发送电邮至 PrivacyOfficer@computershare.com.hk。 Please cut the mailing label and stick it on an envelope to return this form to us.Mailing Label 邮 寄 标 签 No postage is necessary if posted in Hong Kong.Computershare Hong Kong Investor Services Limited香港中央证券登记有限公司 Freepost No. 简便回邮号码：37 当 阁下寄回此回条时，请将邮寄标签剪贴于信封上。 Hong Kong 香港 如在本港投寄， 阁下无需支付邮费或贴上邮票。