In China, we conduct oil and gas exploration, development and production primarily through independent operations and cooperation projects.

Independent operations: We increase reserves and production primarily through independent exploration and exploitation. As of the end of 2025, approximately 90.0% of net proved reserves and approximately 87.8% of net production in China were from our independent oil and gas fields.

Cooperation projects: We cooperate with partners through product sharing contracts (“PSCs”) in oil and gas resources (including crude oil and natural gas) exploitation and development. China National Offshore Oil Corporation (“CNOOC Group”), our controlling shareholder, has the exclusive right to enter into PSCs with foreign contractors to cooperate in the exploration, exploitation and production of oil and gas resources in offshore China where acreage is open to foreign cooperation. CNOOC Group has transferred to the Company all its rights and obligations under the existing and future PSCs (except those rights and obligations related to the management and supervision that should be implemented by a State Corporation).

Bohai is the largest crude oil production base in China and also the most important crude oil producing area for the Company. In 2025, the Company made three new discoveries and successfully appraised 10 oil and gas bearing structures in Bohai. Among them, the successful appraisal of Qinhuangdao 29-6 Oilfield, with proved in-place volume of 100-million-ton, demonstrated the promising exploration prospects of the shallow lithologic area in Bohai. During the year, Bozhong 26-6 Oilfield Development Project (Phase I), Luda 5-2 North Oilfield Phase II Development Project, Caofeidian 6-4 Oilfield Comprehensive Adjustment Project, and Kenli 10-2 Oilfield Group Development Project (Phase I) all were put into operation.

Western South China Sea is the Company’s important natural gas production areas. In 2025, the Company made two new discoveries and successfully appraised 13 oil and gas bearing structures in the Western South China Sea. Among them, Weizhou 10-5 and Weizhou 10-5 South were newly discovered, demonstrating the broad exploration prospects of the buried-hill area in the Beibu Gulf Basin. Multiple oil and gas bearing structures including Lingshui 17-2 and Lingshui 25-1 were successfully appraised, showing remarkable results in integrated exploration and development for progressive reserve growth. During the year, Dongfang 29-1 Gas Field Development Project, Wenchang 19-1 Oilfield Phase II Project, Wenchang 9-7 Oilfield Development Project, Weizhou 5-3 Oilfield Development Project, Dongfang 1-1 Gas Field Block 13-3 Development Project, Wenchang 16-2 Oilfield Development Project, and Weizhou 11-4 Oilfield Adjustment and Satellite Fields Development Project were put into operation.

Eastern South China Sea is one of the Company’s important crude oil producing areas. In 2025, the Company made one new discovery and successfully appraised three oil and gas bearing structures in the Eastern South China Sea. In particular, Lufeng 13-8 Oilfield was successfully appraised, and its reserve scale was expanded. During the year, Panyu Block 10/11 Joint Development Project and Xijiang Oilfield Group Block 24 Development Project were successfully put into operation.

East China Sea is the Company’s natural gas producing area for the Yangtze River Delta region. In 2025, the Company continued to optimize infill drilling in the East China Sea, sustained stable production of producing fields, advanced the transformation of unmanned and minimally manned offshore platforms, and accelerated the construction of offshore smart oil and gas fields.

We mainly engaged in the exploration, development and production of unconventional natural gas resources onshore China. We have established three major production bases, Linxing, Shenfu and Panhe, in the eastern edge of the Ordos Basin and the Qinshui Basin. In 2025, the Company deepened the theory of coalbed methane enrichment in deep play, accelerated the appraisal of various types of gas fields including deep and medium-shallow plays, and added proved in-place natural gas volume exceeding 100 billion cubic meters, among them, deep coalbed methane accounts for more than 80%. All these demonstrated the promising exploration prospects for deep coalbed methane.

By the end of 2025, China’s net proved reserves stood at 5,015.7 million BOE. Among them, net proved reserves of crude and liquids reached 3,385.7 million BOE; net proved reserves of natural gas reached 9,700.0 bcf. Our net proved oil and gas reserves have maintained steady growth. During the year, China’s net oil and gas production amounted to 536.9 million BOE, with a year-on-year growth of 9.0%. Among them, net production of crude and liquids reached 401.8 million BOE, with a year-on-year growth of 6.7%; net production of natural gas reached 799.5 bcf, with a year-on-year growth of 16.7%.

The Company boasts a diversified asset portfolio and international operation and management capabilities, and holds interests in a number of world-class oil and gas projects, with assets spanning more than 20 countries and regions around the world, including Indonesia, Australia, Nigeria, Iraq, Uganda, Argentina, the United States, Canada, the United Kingdom, Brazil, Guyana, and the United Arab Emirates.

Asia (excluding China) is the first overseas region the Company entered into. Currently, the Company owns oil and gas assets mainly in Indonesia and the United Arab Emirates and also acts as the main contractor of technical services contracts for the Missan oilfields in Iraq. In 2025, all projects maintained stable production. In addition, the Company successfully acquired four new exploration projects, e.g. Block 7 in Iraq, Zhylyoi Block in Kazakhstan, and Gaea and Gaea II blocks in Indonesia.

Currently, the Company’s oil and gas assets in Oceania are mainly located in Australia. The North West Shelf LNG Project in Australia supplies gas to the end-users including the Dapeng LNG Regasification Terminal in Guangdong, China, and its incremental gas is sold in spot LNG market independently. In 2025, the NWS LNG Project maintained stable production, achieving incremental gas production that exceeded expectations.

Africa is an important source of oil and gas production for the Company overseas. The Company’s assets in Africa are primarily located in Nigeria and Uganda. In 2025, the Company successfully implemented production enhancement measures in Blocks PML 2/3/4 and PPL 261 in Nigeria, such as infill drillings and injection-production optimization, and the oilfield decline rate has been effectively mitigated and controlled. For the Kingfisher Project in Uganda, all pre-drilling site preparation works had been completed, oilfield production equipment and facilities had their installation completed, and cable laying is currently underway. The Company will continue to work actively with its partners and the government of Uganda to bring the projects into production.

North America is one of the Company’s major overseas oil and gas reserves regions. The Company holds interests in oil and gas blocks in the U.S., Canada, Trinidad and Tobago in North America. The Company owns 100% working interests in Long Lake Project in Canada. In 2025, the production of Long Lake project continued to increase due to the efficient implementation of infill drillings, as well as the rapid ramping up of Long Lake Northwest project. In 2025, a subsidiary of CNOOC Limited completed the Stock Purchase Agreement with INEOS Energy, involving the Company’s upstream oil and gas business located in the U.S. Gulf of Mexico, mainly consisting of non-operating interests in oil and gas projects including the Appomattox and Stampede fields.

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South America has become the region with the largest overseas oil and gas reserves and production of the Company and is a significant source of production growth for the Company. The Company holds interests in oil and gas blocks in Brazil, Guyana and Colombia in South America, as well as a 50% interest in BC ENERGY INVESTMENTS CORP. (“BC”) in Argentina.

Brazil deepwater area is one of the world’s most important oil and gas development regions. CNOOC Limited holds interests in Mero and Buzios oilfields in Brazil, respectively. In 2025, Mero4 Project of Mero oilfields in Brazil was successfully put into production and total of four phases of projects have been put into production in this oilfield. Buzios7 of Buzios oilfields was also successfully put into production and 11 units of Buzios oilfields are expected to be in operation by 2027.

The Stabroek block in offshore Guyana is one of the global exploration hotspots in recent years, and CNOOC Limited holds a 25% interest in the block. In 2025, two oilfields, Lukanani and Ranger, were successfully appraised, and Yellowtail Project was put into production smoothly. Four projects have commenced production in the Stabroek block. By 2030, the block is expected to have eight projects in operation.

In Europe, CNOOC Limited holds interests in oil and gas fields such as Buzzard and Golden Eagle in the U.K. North Sea, and holds interests in Arctic LNG 2 LLC in Russia.

By the end of 2025, overseas net proved reserves stood at 2,757.4 million BOE. Among them, net proved reserves of crude and liquids reached 2,416.8 million BOE; net proved reserves of natural gas reached 1,940.3 bcf. Our net proven oil and gas reserves have maintained a steady growth trend. In 2025, the Company’s overseas net oil and gas production amounted to 240.4 million BOE, with a year-on-year growth of 2.7%. Among them, net production of crude and liquids reached 197.9 million BOE, with a year-on-year growth of 3.9%; net production of natural gas reached 237.9 bcf, with a year-on-year decrease of 2.6%.