Cenozoic Sedimentary Characteristics of the East China Sea Shelf Basin and an Evaluation of the Suitability of Geological Storage of Carbon Dioxide in the Saline Water Layer

Carbon sequestration in the sea area, with the advantages of high storage potential, high safety, low environmental impact, and a long storage period, serves as an important way to achieve the goals of "carbon peaking and carbon neutrality". The East China Sea Shelf Basin has a large area, and the target layer of carbon storage has a large thickness and wide distribution. Due to the high tectonic stability of the basin and the absence of earthquakes of magnitude 7 or higher, the basin is a subcooled-subthermal basin in terms of geothermal field characteristics. In addition, the basin has a high degree of oil and gas exploration and development, some of the reservoirs are in production depletion, the oil and gas transmission pipeline network is well developed, and the development engineering data are informative. Therefore, it enjoys the characteristics of shallow seawater depth; being close to the surrounding industrial areas; and having a short transmission distance, large effective space, and mature engineering conditions. Among the oil-and-gas-bearing basins in China's waters, the suitability of carbon dioxide (CO2) geological storage in the saline water layer of the East China Sea Shelf Basin is highly suitable. The analytic hierarchy process (AHP) is used to comprehensively evaluate the suitability of CO2 geological storage in the saline water layer of each tectonic unit in the basin, and it is concluded that Taipei Depression and Zhedong Depression are highly suitable zones, Changjiang Depression and Haijiao Uplift are moderately suitable zones, and Yushan East Uplift, Hupijiao Uplift, and Pengjiayu Depression are generally suitable zones.