Abstract
In 2025,China’s offshore oil and gas industry achieved a strategic transition from isolated ultra-deepwater breakthroughs to scaled and stable production.The full commissioning of Phase II of the “Deep Sea No. 1” ultra-deepwater gas field on 25 June 2025 marked the large-scale production stage of China’s first self-operated ultra-deepwater gas field.All 23 subsea gas wells were put into operation; maximum operating water depth exceeded 1,500 m,maximum well depth exceeded 5,000 m,peak daily gas output reached 15 million m³,and total proven gas reserves exceeded 150 billion m³.In April 2025, CNOOC’s independently developed sixth-generation ultra-deepwater semi-submersible drilling platform completed a 3,500–4,000 m ultra-deepwater exploration well in the South China Sea in only 11.5 days,setting a national record for ultra-deepwater drilling cycle.The “Deep Sea No. 1” energy station,the world’s first 100,000-tonne-class deepwater semi-submersible production and storage platform,integrated three world-class innovations and 13 domestically pioneered technologies.Its development model—subsea production systems,shallow-water jacket platforms,and remote-control systems for deepwater semi-submersible platforms—spans over 170 km and more than 1,500 m of water depth,addressing deepwater,high-temperature, and high-pressure challenges.Internationally, the Búzios Phase VI project in Brazil,in which CNOOC participated, was commissioned on 31 December 2025,marking the first large-scale application of China’s ultra-deepwater engineering technology to an international large oil and gas field.These advances are underpinned by China’s deepwater resource potential:over half in deepwater, while offshore crude output reached about 65.5 million tonnes in 2024,contributing over 80% of domestic crude production growth.They strengthen national energy security,drive high-end equipment innovation,and enhance China’s role in global deepwater energy cooperation.
Keywords:ultra-deepwater oil and gas;Deep Sea No. 1;semi-submersible production platform;subsea production system;energy security; international energy cooperation
Biography
Cong Wei,professor，Ph.d on economic.Now he is the Principal research fellow of CNOOC Energy Economics Institute，and his office is now based in Beijing China.deputy director of Southeast office，He was once a post-doctoral reseacher in Academy of Chinese Energy Strategy. He has also been the director of ASEAN Office(Based in Bangkok,Thailand)and the director of Latin America Office(Based in Santiago de Chile) of GEIDCO（Global Energy Interconnection Development and Cooperation Organization）,and also been thevice director of economics research office at CPPEI(Petrochina Planning and Engineering Institute),and served as a civil-servant at Policy and Law department of National Energy Adiministration of PRC during 2008-2013.He was the chief member of “China’s Energy Policy:2012” white paper dafting penal.His main research area involves energy economy and its policies,market-oriented reform of energy system,the natrual gas economy and its developmetal strategies etc.Now he also takes the post of the editorial board member of ENERGY REVIEWS,the councilor of the Energy committee of System Engeering Sociaty of China.His published book include China’s Path To Low-cabon Energy Sociaty,The Path Selection of the Ragulation Policies about the Coal Productive Capicity.
