China National Offshore Oil Corporation (CNOOC) announced on Saturday that construction has officially started on a carbon capture, utilization and storage (CCUS) project at the Dongfang 1-1 gas field in south China's Hainan Province.

The project includes the construction of two new jacket platforms and an undersea pipeline connected to the existing production facilities of the Dongfang 1-1 gas field.

It marks China's first demonstration initiative applying offshore carbon injection technology to enhance natural gas production.

Carbon injection for enhanced gas recovery is a specialized branch of CCUS technology. Its core principle is to turn carbon dioxide emitted during natural gas extraction into a valuable resource. After being captured and purified, the carbon dioxide is pressurized and injected back into gas-bearing reservoirs, where it acts as a driving force to unlock hard-to-recover natural gas reserves.

"With the new project, we will move the decarbonization process, originally located at onshore processing plants, to the offshore platform itself, achieving carbon reduction at the source. Compared with traditional processes, the technology used here offers higher equipment integration, lower energy consumption, and better recovery of hydrocarbon components," said Yu Fasong, head of the Dongfang 1-1 CCUS project at CNOOC Hainan.

The Dongfang 1-1 gas field, China's first self-operated offshore gas field and the country's first offshore high-CO2 gas field, has been in production since 2003, with cumulative natural gas output exceeding 50 billion cubic meters.

"When fully operational, the project is expected to inject up to about 1.2 million tons of carbon dioxide into the formation annually. This is of great significance for enhancing marine energy and resource development capabilities and supporting China's dual carbon goals," Yu said.

Upon completion, the project will enhance the transportation capacity of the subsea pipeline network in the Yinggehai Sea, support the cost-effective development of more carbon-rich natural gas resources in the region, and help sustain long-term stable production of the entire Dongfang gas field cluster.