China's First Offshore Carbon-Injection, Gas-Recovery Platform Installed, with the Country's First Offshore Low-Temperature Decarbonisation System Shipped

The Dongfang 1-1 project has put its new platform in place and completed the country's first offshore low-temperature decarbonisation package, which now goes to sea as part of a capture-and-injection loop.

China National Offshore Oil Corporation's Dongfang 1-1 gas field project for carbon capture, storage and utilisation has completed the offshore installation of its new platform, and the project's core production-treatment equipment — the country's first offshore low-temperature decarbonisation system — has completed construction and been shipped. The Hainan channel of People's Daily Online (人民网海南频道) reported the milestone on 11 August 2026 (1).

The project

The same report describes the Dongfang 1-1 development as China's first offshore demonstration of the "inject carbon, boost gas" technique, building an integrated loop offshore that captures and purifies CO₂, stores it in the formation, and drives additional gas recovery. Once in full operation, the project is expected to store more than 1 million tonnes of CO₂ a year in the formation (1).

What was installed

The platform that completed offshore installation is the first three-legged jacket platform the company has deployed in the Hainan sea area, and is the facility through which the project will inject CO₂ into the formation. The jacket weighs 1,400 tonnes and the topsides module 1,100 tonnes, installed separately. The report states the jacket's plan-position error was held to metre level and its elevation accuracy to millimetre level (1).

The decarbonisation package

The low-temperature decarbonisation system is described as the project's core equipment for separating and purifying CO₂ with high efficiency. It is built from three modules — a molecular-sieve adsorption unit for dehydration and mercury removal, a membrane-plus-low-temperature-rectification decarbonisation unit, and a refrigeration unit — carrying 26 items of individual equipment at a total weight of 2,252 tonnes. The report describes its land-side construction and shipment as an independent breakthrough in China's offshore oil-and-gas low-temperature decarbonisation package-building capability (1).

The compression route on the earlier offshore project

The injection duty on the earlier Enping 15-1 offshore CCS/CCUS project is documented separately. The project team states it took the compression route from three stages to four — described as a four-stage pressurisation with dual-path stabilisation scheme — to hold the CO₂ in the supercritical state at an injection pressure above 180 kg, with core equipment and instrumentation independently developed and 100 per cent domestic equipment supply (2). The first domestic supercritical CO₂ injection compressor package for that project was supplied to the Enping 15-1 platform and placed in operation in 2023, forming two CO₂ treatment and injection trains with a stated capacity of 240,000 standard cubic metres per day each (3).

Offshore CCUS is described in the same accounts as harder than onshore because the southern sea area's temperature and humidity swings make the CO₂ prone to condensation, which can block the system and corrode equipment (2).

What the source does not state

The Dongfang 1-1 reports do not name the compressor supplier, the machine class, the number of compression stages, the discharge pressure or the drive. They do not state where the CO₂ is captured from at the site, the purity achieved by the decarbonisation package, the injection well count or depth, the target formation, or the project's schedule for first injection and commercial operation. The stated 1 million tonnes a year is a full-operation expectation and the reports give no commissioning date for it. On Enping 15-1, the "above 180 kg" injection pressure is stated as a scheme target rather than as a measured wellhead value, and no compressor rating, discharge temperature or availability figure is published.

Where this connects on this site

Sources

#	Basis
1	Offshore installation completed for the new platform of CNOOC Hainan's Dongfang 1-1 CO₂ capture, storage and utilisation project; the low-temperature decarbonisation system completing construction and being shipped; described as China's first offshore demonstration of the inject-carbon-boost-gas technique with an integrated offshore loop of capture, purification, formation storage and enhanced gas recovery; more than 1 million tonnes of CO₂ a year into the formation expected at full operation; first three-legged jacket platform in the Hainan sea area, jacket 1,400 t and topsides 1,100 t installed separately, plan-position error at metre level and elevation accuracy at millimetre level; the decarbonisation system made up of a molecular-sieve dehydration and mercury-removal unit, a membrane-plus-low-temperature-rectification decarbonisation unit and a refrigeration unit, carrying 26 items of individual equipment at 2,252 t total — 人民网海南频道, 2026-08-11, https://hi.people.com.cn/BIG5/n2/2026/0811/c231190-41664372.html
2	The four-stage pressurisation with dual-path stabilisation scheme on the Enping 15-1 offshore CCUS project, taking compression from three stages to four to keep the CO₂ supercritical above 180 kg injection pressure; core equipment and instrumentation 100% independently developed with 100% domestic equipment supply; the southern sea area's temperature and humidity swings making CO₂ prone to condensation, system blockage and equipment corrosion — 中国能源产业发展网, 2026-02, https://www.ccedia.com/energy_detail/c-_detailId%3D2026832528003145728.html
3	The first domestic supercritical CO₂ injection compressor placed in operation at the Enping 15-1 platform in 2023, forming two CO₂ treatment and injection trains each stated at 240,000 standard cubic metres per day — 压缩机网, 2023-06-13, http://www.compressor.cn/News/qyzc/2023/0613/123806.html