China has started operating its first offshore carbon capture, utilisation and storage project at the Enping 15-1 oil platform in the Pearl River Mouth Basin in the northern part of the South China Sea.
Located around 200km southwest of Shenzhen, the project captures carbon dioxide generated during oil production, compresses it into a supercritical state, and injects it into subsurface oil reservoirs for long-term storage.
Once compressed into a supercritical state, the CO2 behaves more like a liquid than a gas, allowing for higher density and storage capacity in underground reservoirs. This state also enables easier penetration into pore spaces and improved mixing with crude oil, enhancing oil recovery, which the project is designed to support.
The system is currently injecting around eight tonnes of CO2 per hour, with plans to increase capacity to 17 tonnes per hour following equipment upgrades, according to operator China National Offshore Oil Corporation (CNOOC).
The Enping 15-1 platform is Asia’s largest offshore oil production facility and forms part of a field that produces more than 7,500 tonnes of crude oil per day. The oilfield has naturally high levels of CO2, which would traditionally be extracted alongside crude oil and released, posing corrosion risks to equipment and adding to emissions.
By reinjecting captured CO2 into the reservoir, the project aims to both enhance oil recovery and sequester carbon. While CNOOC presents this as a dual-benefit model that reduces emissions and operating costs, the use of CO2 for enhanced oil recovery (EOR) remains controversial.
The Enping 15-1 oilfield platform ©China Classification Society
Critics argue that CO2-EOR may undermine climate targets by enabling further fossil fuel production, while others view it as a transitional step toward broader carbon management.
In fact, the International Energy Agency notes that while CO2-EOR can reduce the carbon intensity of oil production, it does not automatically result in net carbon removal. Achieving carbon-negative oil would require careful monitoring, permanent storage of injected CO2, and strict limits on associated emissions across the supply chain.
It is not yet clear whether China has rules in place, or independent oversight, to track how securely the captured CO2 is stored offshore, or to measure the overall climate impact of using it to extract more oil.
Without transparent reporting and oversight, it is difficult to assess whether such initiatives deliver genuine emissions reductions.
However, Wan Nianhui, general manager of the Enping oilfield operation area believes that the project will advance the country’s carbon reduction goals.
“Over the next decade, we will inject more than one million tonnes of CO2 and drive an increase in crude oil production of 200,000 tonnes,” he said.
“This is significant for ensuring national energy security and advancing toward carbon peak and carbon neutrality goals.”
CNOOC says the demonstration project has already injected nearly 200,000 tonnes of CO2 since its mid-2023 launch. It is being positioned as a demonstration model for large-scale, offshore carbon reduction across the Guangdong-Hong Kong-Macao Greater Bay Area.
There are thought to be around 65 commercial CCUS projects in operation globally, but the vast majority are land-based. Offshore CCUS remains relatively rare due to technical complexity and cost.
