China Achieves Full-Chain Breakthrough in Offshore CCUS Technology: Enping Project Injects Over 300,000 Tonnes of CO₂
China National Offshore Oil Corporation (CNOOC) announced today that the Enping 15-1 Oilfield CCUS Demonstration Project, the nation's first offshore carbon capture, utilization, and storage (CCUS) initiative, has cumulatively injected over 300,000 tonnes of carbon dioxide at scale. The project has successfully transformed industrial off-gas into a green resource, pioneering a new marine energy cycle model of "utilizing carbon for enhanced oil recovery while storing it in reservoirs." This milestone signifies that China has mastered the full-chain core technologies for offshore CCUS.
Green Transformation of Asia's Largest Offshore Platform
Located in the Pearl River Mouth Basin, the Enping 15-1 platform is the largest offshore crude oil production platform in Asia, with the developed oilfield cluster achieving a peak daily crude output exceeding 7,500 tonnes. The associated gas from this field contains up to 95% carbon dioxide. Conventional development methods would not only severely corrode equipment and pipelines while exacerbating the greenhouse effect, but also result in relatively low reservoir recovery rates.
CNOOC designated this project as a key energy conservation and carbon reduction initiative under the 14th Five-Year Plan. After four years of dedicated research and development, over ten domestically pioneered technologies were established. In June 2023, China's first offshore Carbon Capture and Storage (CCS) demonstration project commenced operations here. On May 22, 2025, the project was upgraded to CCUS, achieving a transition from pure carbon sequestration to carbon capture for enhanced oil recovery.
Three Core Technologies Overcome Offshore CCUS Challenges
Precise Regulation of Supercritical Carbon Dioxide
The project employs supercritical CO₂ enhanced oil recovery (CO₂-EOR) technology. Carbon dioxide is pressurized above 7.38 MPa and heated above 31.1°C to reach a supercritical state—exhibiting the high diffusivity of a gas and the high density of a liquid—thereby significantly enhancing storage capacity and pumping efficiency. To maintain this delicate balance, the project team pioneered a "Four-Stage Compression with Dual-Path Stabilization" scheme, upgrading conventional three-stage compression to four stages. This innovation ensures the carbon dioxide remains in a stable supercritical state even under reinjection pressures exceeding 180 kilograms. Furthermore, the project achieved 100% independent research and development of core equipment and instrumentation, establishing China's first complete offshore CCUS equipment package system. Additional protective measures have been added, including precise pressure and temperature control technology and dual-loop systems, laying a solid foundation for large-scale reinjection operations. Hengda's equipment can also meet the standards of precise pressure and temperature control, helping customers achieve energy conservation and carbon reduction.
Efficient Injection via "Repurposing Old Wells + Zonal Injection"
The project innovatively retrofitted depleted old wells as reinjection conduits, saving over RMB 10 million in drilling costs and completing the work seven days ahead of schedule. Leveraging independently developed technology integrating "hydraulic-controlled intelligent fine zonal injection and distributed fiber optic monitoring," precise gas injection into different reservoir layers is achieved. This effectively prevents carbon dioxide channeling and substantially improves oil displacement efficiency.
Overcoming the Global Challenge of "Sweet Corrosion"
To address "sweet corrosion"—caused by carbon dioxide dissolving in water to form carbonic acid, which accelerates geometrically under high pressure—CNOOC independently developed an anti-CO₂ corrosion cement slurry system and specialized drilling fluids. All equipment in contact with carbon dioxide is specially treated for corrosion prevention. The capture area cabinets meet the highest C5-M anti-salt spray rating and feature additional acid-gas-resistant coatings, ensuring decades of safe and stable wellbore operation.
Project Benefits and Industry Outlook
As of February 2026, the project's cumulative carbon injection of 300,000 tonnes is equivalent to planting approximately 6.6 million trees. The current injection rate stands at 8 tonnes per hour, slated to increase to 17 tonnes per hour in the future, with peak single-well annual incremental oil production reaching 15,000 tonnes. Over the projected 10-year operational period, the project is expected to cumulatively store over one million tonnes of CO₂ while producing approximately 200,000 tonnes of incremental crude oil.
Currently, most of the 65 commercial CCUS projects globally are concentrated onshore, with offshore ventures remaining exceedingly rare. China's offshore geological carbon storage potential is estimated at 2.58 trillion tonnes, indicating vast development prospects. Following the Enping project, construction commenced on April 11, 2026, for China's first offshore "injecting carbon to enhance gas recovery" initiative—the Dongfang 1-1 Gas Field CCUS Demonstration Project. On July 1, 2026, China's first batch of 12 national CCUS standards will be officially implemented, propelling the industry into a new phase of large-scale commercial development.