Suitability assessment on CO₂ storage in offshore basins of China based on AHP and fuzzy comprehensive evaluation

CO₂ emissions lead to global temperature changes and “dominoes are overturned”, triggering a series of environmental problems one after another. Therefore, CO₂ offshore storage is an important issue to achieve the goal of “carbon peak and carbon neutrality”. Taking China offshore basins as the research object, the method of AHP (analytic hierarchy process) and fuzzy comprehensive evaluation was used, three aspects of storage security, storage scale and storage feasibility were considered, and a CO₂ storage suitability evaluation index system was constructed with three first-level indicators and eight second-level indicators, upon which the CO₂ storage suitability and favorable areas of 10 offshore basins in China was assessed. Results shows that the offshore basin CO₂ suitability in a descendant order is: Pearl River Mouth Basin, East China Sea Shelf Basin, Bohai Bay Basin, Beibu Bay Basin, Yinggehai Basin (Yinggehai Formation), South Yellow Sea Basin, North Yellow Sea Basin, Qiongdongnan Basin, Taixi Basin, and Southwest Taiwan Basin. Among them, the Pearl River Mouth Basin and the East China Sea Shelf Basin can be regarded as the preferred basins for CO₂ offshore storage.