| Name of entity                                             |   | Our interest |   | Jurisdiction of incorporation |
|------------------------------------------------------------|--------|--------------|--------|-------------------------------|
| CNOOC China Limited                                   |   | 100%         |   | Tianjin, PRC             |
| CNOOC International Limited                                |   | 100%         |   | British Virgin Islands   |
| China Offshore Oil (Singapore) International Pte Ltd  |   | 100%         |   | Singapore                |
| CNOOC Finance (2003) Limited                               |   | 100%         |   | British Virgin Islands   |
| Malacca Petroleum Limited                                  |   | 100%         |   | Bermuda                  |
| OOGC America LLC                                           |   | 100%         |   | Delaware, USA            |
| OOGC Malacca Limited                                       |   | 100%         |   | Bermuda                  |
| CNOOC Southeast Asia Limited                               |   | 100%         |   | Bermuda                  |
| CNOOC Africa Holding Ltd.                                  |   | 100%         |   | British Virgin Islands   |
| CNOOC Africa Ltd.                                          |   | 100%         |   | British Virgin Islands   |
| CNOOC Africa (UK) Limited                                  |   | 100%         |   | London, U.K.             |
| CNOOC SES Ltd.                                             |   | 100%         |   | Labuan, F.T.,Malaysia         |
| CNOOC Poleng Ltd.                                          |   | 100%         |   | Labuan, F.T.,Malaysia         |
| CNOOC Madura Ltd.                                          |   | 100%         |   | Labuan, F.T.,Malaysia         |
| CNOOC NWS Private Limited                                  |   | 100%         |   | Singapore                |
| CNOOC Australia E&P Pty Ltd                            |   | 100%         |   | Australia                |
| CNOOC Wiriagar Holding Limited                             |   | 100%         |   | Labuan, F.T.,Malaysia         |
| CNOOC Muturi Holding Limited                          |   | 100%         |   | Labuan, F.T.,Malaysia         |
| CNOOC Muturi Limited                                       |   | 100%         |   | The Isle of Man          |
| CNOOC Belgium BVBA                                         |   | 100%         |   | Belgium                  |
| CNOOC Australia Limited                                    |   | 100%         |   | British Virgin Islands   |
| CNOOC Exploration & Production Nigeria Limited    |   | 100%         |   | Nigeria                  |
| CNOOC Hong Kong Holding Limited                       |   | 100%         |   | Hong Kong                     |

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| CNOOC Myanmar Holding Ltd.                        |   | 100%   |   | British Virgin Islands       |
|--------------------------------------------------------|--------|--------|--------|------------------------------|
| CNOOC Myanmar Ltd.                                     |   | 100%   |   | British Virgin Islands  |
| CNOOC Middle East (Qatar) Limited                 |   | 100%   |   | British Virgin Islands  |
| CNOOC Congo SA                                    |   | 100%   |   | Republic of Congo            |
| CNOOC Caspian (Kazakhstan) Ltd.                   |   | 100%   |   | Cayman Islands               |
| CNOOC Singapore Private Limited                        |   | 100%   |   | Singapore               |
| CNOOC Australia Energy Pty Ltd                         |   | 100%   |   | Australia               |
| CNOOC Batanghari Ltd.                                  |   | 100%   |   | Labuan, F.T.,Malaysia        |
| CNOOC Palung Aru Ltd.                                  |   | 100%   |   | Labuan, F.T.,Malaysia        |
| CNOOC FPSO Holding Limited                             |   | 100%   |   | Liberia                 |
| CNOOC Liberia Limited                                  |   | 100%   |   | Liberia                 |
| CNOOC Uganda (BVI) Ltd                                 |   | 100%   |   | British Virgin Islands  |
| De coöperatieve vereniging CNOOC Netherlands U.A. |   | 100%   |   | The Netherlands              |
|                                                   |   |   |   |                         |
| CNOOC Netherlands B.V.                                 |   | 100%   |   | The Netherlands         |
| CNOOC Uganda Ltd                                       |   | 100%   |   | Uganda                  |
| CNOOC Deepwater Development Limited               |   | 100%   |   | Zhuhai, PRC             |
| CNOOC Hainan Dock Limited                              |   | 100%   |   | Hainan, PRC             |
| CNOOC Iraq Limited                                     |   | 100%   |   | British Virgin Islands       |
|                                                   |   |   |   |                         |
| CNOOC Finance (2011) Limited                           |   | 100%   |   | British Virgin Islands       |
|                                                   |   |   |   |                         |
| CNOOC Algeria (BVI) Limited                            |   | 100%   |   | British Virgin Islands       |
|                                                   |   |   |   |                         |
| CNOOC Reserves Fund I, Ltd.                            |   | 100%   |   | Cayman Islands               |
|                                                   |   |   |   |                         |
| CNOOC Luxembourg S.à r.l.                         |   | 100%   |   | Luxembourg                   |
|                                                   |   |   |   |                         |
| CNOOC Finance (2012) Limited                           |   | 100%   |   | British Virgin Islands       |

----

| CNOOC Finance (2013) Limited                                      |   | 100%            |   | British Virgin Islands             |
|-------------------------------------------------------------------|--------|-----------------|--------|------------------------------------|
|                                                              |   |            |   |                               |
| Tainan-Chaoshan Petroleum Operating Company Limited*              |   | 50%             |   | British Virgin Islands             |
|  Husky - CNOOC Madura Limited *                         |   |  40%  |   |  British Virgin Islands  |
| Chaoyang Petroleum (BVI) Limited*                            |   | 50%             |   | British Virgin Islands        |
| Chaoyang Petroleum (Trinidad) Block 3A Limited*              |   | 50%             |   | Barbados                           |
| Chaoyang Petroleum (Trinidad) Block 2C Limited*              |   | 50%             |   | Barbados                           |
| Bridas Corporation*                                               |   | 50%             |   | British Virgin Islands             |
|                                                              |   |            |   |                               |
| Axion Energy Holding Ltd. *                                       |   | 50%             |   | British Virgin Islands             |
|                                                              |   |            |   |                               |
| PNG Energy Limited                                           |   | 70%             |   | British Virgin Islands             |
| GINI Energy Ltd                                              |   | 70%             |   | Papua New Guinea                   |
| CNOOC Iceland ehf.                                                |   | 100%            |   | Iceland                            |
|                                                              |   |            |   |                               |
| CNOOC Luxembourg HoldingS.à r.l.                             |   | 100%            |   | Luxembourg                         |
|                                                              |   |            |   |                               |
| CNOOC PETROLEUM BRASIL LTDA                             |   | 100%            |   | Brazil                             |
| CNOOC International Energy Services (Beijing) Limited   |   | 100%            |   | Beijing, PRC                       |
| Aurora Liquefied Natural GasLtd.                             |   | 60%             |   | Alberta, Canada               |
| Canadian Nexen Petroleum EastAl Hajr Ltd.                    |   | 100%            |   | Alberta, Canada               |
| Canadian Petroleum Yemen Limited                             |   | 100%            |   | Jersey                        |
| CanadianOxy OffshoreProduction Co.                           |   | 100%            |   | Delaware, USA                 |
| CNOOC Canada Energy Ltd.                                          |   | 100%            |   | British Columbia, Canada           |
|                                                              |   |            |   |                               |
| CNOOC Nexen Finance (2014)ULC                                |   | 100%       |   | Nova Scotia, Canada           |
|                                                              |   |            |   |                               |
| CNOOC Nexen PetroleumGuyana Limited                               |   | 100%       |   | Barbados                           |

----

| CNOOC UK Limited                                         |   | 100%       |   | England and Wales  |
|---------------------------------------------------------------|--------|------------|--------|-------------------------|
| ICH Capital Management HungaryLimited Liability Company  |   | 100%       |   | Hungary            |
| ICM Assurance Ltd.                                       |   | 100%       |   | Barbados           |
| ICM Holdings Limited                                     |   | 100%       |   | Jersey             |
| International CapitalHoldings Limited                    |   | 100%       |   | Malta              |
| Nexen Brasil ExploraçãoPetróleo Ltda.     |   | 100%       |   | Brazil             |
| Nexen E & P ServicesNigeria Limited                  |   | 100%       |   | Nigeria            |
| Nexen Energy AcquisitionsHoldings Limited                |   | 100%       |   | Jersey             |
| Nexen Energy CapitalManagement U.S.A. Inc.                    |   | 100%  |   | Delaware, USA           |
|                                                          |   |       |   |                    |
| Nexen Energy HoldingsInternational Limited               |   | 100%       |   | Jersey             |
| Nexen Energy HoldingsU.S.A. Inc.                              |   | 100%       |   | Delaware, USA      |
| Nexen Energy MarketingEurope Limited     |   | 100% |   | England and Wales         |
|-----------------------------------------------|--------|------|--------|--------------------------------|
| Nexen Energy MarketingNigeria Limited    |   | 100% |   | Nigeria                   |
| Nexen Energy MarketingU.S.A. Inc.        |   | 100% |   | Delaware, USA             |
| Nexen Energy ServicesInternational Ltd.  |   | 100% |   | England and Wales         |
| Nexen Energy Services U.S.A.Inc.         |   | 100% |   | Delaware, USA             |
| Nexen Energy ULC                         |   | 100% |   | British Columbia, Canada  |
| Nexen Ettrick U.K. Limited               |   | 100% |   | England and Wales         |
| Nexen Field ServicesNigeria Limited      |   | 100% |   | Nigeria                   |
| Nexen Holdings U.S.A. Inc.               |   | 100% |   | Delaware, USA             |

----

| Nexen Holdings WestAfrica Limited                           |   | 100%       |   | Jersey             |
|------------------------------------------------------------------|--------|------------|--------|-------------------------|
| Nexen MarketingSingapore Pte Ltd.                           |   | 100%       |   | Singapore          |
| Nexen New Venture JerseyLimited                             |   | 100%       |   | Jersey             |
| Nexen No. 8 Ltd.                                            |   | 100%  |   | Alberta, Canada    |
| Nexen Oil & Gas HoldingsU.S.A. Inc.                     |   | 100%       |   | Delaware, USA      |
| Nexen Oilfield ServicesNigeria Limited                      |   | 100%       |   | Jersey             |
| Nexen Petroleum ColombiaLimited                             |   | 100%       |   | Jersey             |
| Nexen Petroleum DeepwaterNigeria Limited                    |   | 100%       |   | Nigeria            |
| Nexen Petroleum Dragon U.K.Limited                          |   | 100%       |   | England and Wales  |
| Nexen Petroleum Exploration and Production Nigeria Limited  |   | 100%       |   | Nigeria            |
| Nexen Petroleum Nigeria Limited                             |   | 100%       |   | Nigeria            |
| Nexen Petroleum Offshore U.S.A. Inc.                        |   | 100%       |   | Delaware, USA      |
| Nexen Petroleum OperationsYemen Limited                     |   | 100%       |   | Jersey             |
| Nexen Petroleum Poland Sp.zo.o.                             |   | 100%       |   | Poland             |
| Nexen Petroleum Sales U.S.A.Inc.                            |   | 100%       |   | Texas, USA         |
| Nexen Petroleum U.K. HoldingsLimited                        |   | 100%       |   | England and Wales  |
| Nexen Petroleum U.K. Limited                                |   | 100%       |   | England and Wales  |
| Nexen Petroleum U.S.A. Inc.                                 |   | 100%       |   | Delaware, USA      |
| Nexen Resource Holdings U.K.Limited                         |   | 100%       |   | England and Wales  |
| Nexen Services Jersey Limited                               |   | 100%       |   | Jersey             |

----

| Wascana Energy 2001 Ltd.                     |   | 100%   |   | Saskatchewan, Canada  |
|---------------------------------------------------|--------|--------|--------|----------------------------|
| Canadian Nexen Petroleum Yemen               |   | 100%   |   | Alberta, Canada       |
| Nexen Crossfield Partnership                 |   | 100%   |   | Alberta, Canada       |
| Nexen Marketing                              |   | 100%   |   | Alberta, Canada       |
| Nexen Med Hat-Hatton Partnership             |   | 100%   |   | Alberta, Canada       |
| Nexen Nigerian HoldingsCoöperatief U.A  |   | 100%   |   | The Netherlands       |
| Nexen Oil Sands Partnership                  |   | 100%   |   | Alberta, Canada       |
|                                              |   |   |   |                       |

----