| 1.   | the                Report fully complies with the requirements of Section 13(a) or 15(d)                of                the Exchange Act; and |
|----------------|-------------------------------------------------------------------------------------------------------------------------------------------------|

| 2.   | the                information contained in the Report fairly presents, in all material                respects, the financial condition and results of operations of CNOOC                Limited. |
|----------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   |                                                                                                                                                                                                                                                                                                               |
|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   | By:                /s/ Chengyu                Fu                                            |
|   | Name:                Chengyu Fu                                                                                                                                                                                                                                                                                    |
|   | Title:                Chairman and Chief Executive                Officer                                                                                                                                                                                                                                          |

|   |                                                                                                                                                                                                                                                                                                                               |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   | By:                /s/ Hua                Yang                                               |
|   | Name:                Hua Yang                                                                                                                                                                                                                                                                                                      |
|   | Title:                Executive Director, Executive Vice President andChief Financial                Officer                                                                                                                                                                                                                       |