China Achieves World First in Deep-Water Offshore Carbon Hydrate Sequestration Trial

On November16, 2025, Huairou Laboratory, in collaboration with China National Offshore Oil Corporation (CNOOC), successfully conducted the world’s first deep-water offshore CO₂ hydrate sequestration trial in the Qiongdongnan Basin of the South China Sea at a water depth of 1,695 meters. This landmark achievement signifies China’s pioneering strategic leap from theoretical exploration to practical application in this cutting-edge low carbon technology, setting a new benchmark for global marine carbon sequestration.

The trial’s standout innovation lies in utilizing the deep-water environment’s inherent high pressure and low temperature to efficiently transform liquid CO₂into stable solid hydrates, thereby laying the foundation for long-term and secure carbon storage. During a challenging 20-day operation that endured two typhoons, the research team deployed domestically developed sequestration technologies and equipment to inject liquid CO₂ into sub-seabed sediments, successfully achieving secure storage. Real-time and multi-dimensional monitoring was implemented throughout the full sequestration process, covering CO₂ injection, migration, phase change, and hydrate formation.

The trial has achieved a series of pivotal breakthroughs in core technologies, including accurate prediction of CO₂ phase behavior in deep-water environments, control strategies for hydrate formation interfaces, and a multi-dimensional in-situ monitoring system integrated with acoustic, optical, and electrical sensors. This innovative technical approach offers notable advantages such as broad applicability, reduced geological constraints, and superior long-term stability, highlighting its game-changing potential for advancing future carbon sequestration practices.

The success of this offshore trial not only establishes a robust technical and engineering foundation for the future large-scale deployment of marine carbon sequestration but also secures China a critical first-mover advantage in this emerging field—providing essential support for seizing technological leadership in global marine carbon sequestration.