Deep-Sea Methane Hydrate Safe Extraction System MethaneHarvest Deep Dive: Technical Breakthrough in Extracting Clean Energy from Seafloor Ice

Deep-Sea Methane Hydrate Safe Extraction System MethaneHarvest Deep Dive: Technical Breakthrough in Extracting Clean Energy from Seafloor Ice

MethaneHarvest, a commercial methane hydrate extraction system jointly developed by CNOOC and Japan's Oil, Gas and Metals National Corporation (JOGMEC), announced on August 22, 2030 the completion of its first commercial trial extraction in the Shenhu area of the South China Sea. The system continuously extracted methane hydrate for 30 days, producing a cumulative 1.5 million cubic meters of gas with an average daily output of 50,000 cubic meters, setting a new global record for continuous methane hydrate extraction.

Methane hydrate (commonly known as "combustible ice") is an ice-like solid formed when methane molecules are encased by water molecules, widely distributed in deep-sea sediments and permafrost. It is estimated that the carbon contained in global methane hydrate deposits is twice the total of all known fossil fuels.

MethaneHarvest uses a "depressurization-chemical co-extraction" technology. Traditional depressurization methods have low efficiency and can easily cause formation instability. MethaneHarvest injects trace amounts of carbon dioxide (CO2 replacement method) while depressurizing — CO2 molecules replace methane molecules while maintaining hydrate structure stability, avoiding the risk of formation collapse.

CNOOC's Deep Water Engineering Technology Center director said: "MethaneHarvest solves the most critical safety issue in commercial methane hydrate extraction. The CO2 replacement method not only improves recovery rates but also sequesters CO2 on the seafloor, achieving carbon-neutral or even carbon-negative emissions."

The system's key equipment is an integrated subsea depressurization-injection excavation robot capable of autonomous operation at 1,500 meters water depth. The robot is equipped with real-time formation stress monitoring sensors that automatically halt operations and initiate emergency sealing procedures when formation stability anomalies are detected.

JOGMEC's technical lead said: "Methane hydrate is a transitional energy source toward carbon neutrality. Its carbon emission intensity is 50% lower than coal and 30% lower than natural gas. If it can be commercially extracted at scale, it will significantly alter the global energy landscape."

However, environmental organizations have expressed caution about methane hydrate extraction. Methane is a potent greenhouse gas with 80 times the greenhouse effect of CO2. If methane leaks occur during extraction, it could exacerbate global warming. CNOOC responded that MethaneHarvest's methane leakage rate is controlled below 0.1%, well below safety standards.

Next, CNOOC plans to build the first commercial methane hydrate production platform with an annual output of 100 million cubic meters by 2031.