Potential and pilot significance of CO₂ geological storage in typical sedimentary basin along east Zhejiang coast, China: a case study in Changhe Basin

Carbon capture, utilization, and storage (CCUS) technology is indispensable for achieving global carbon neutrality, and the development of CO₂ geological storage (CCS) will help China to achieve the goal of carbon neutrality. Developed cities along the eastern coast of China have many power plants, refineries, and other large sources of CO₂ emissions, which have a high demand for CO₂ storage. To alleviate the pressure of regional CO₂ emission and to excavate small- and medium-sized sedimentary basins with storage potentials around the eastern coastal area, we selected the Changhe Basin on the south coast of Hangzhou Bay in Zhejiang Province as a research object. Using regional geologic data, we calculated the basin storage potential, and evaluated the significance of pilot small- and medium-sized basins for storage. According to the evaluation of CO₂ geological storage potential of sedimentary basins, we calculated the basin-wide geological storage potential of CO₂ in the saline layer of the basin. Results show that the Changhe Basin has a high potential for CO₂ geological storage in deep saline aquifer. The most potential layers for CO₂ storage are the first sandstone layer in the 2nd Member (Ech²), and the sandstone and conglomerate layers in the 1st Member (Ech¹) of the Paleogene Changhe Formation. The theoretical CO₂ storage capacity could reach 484 million tons and the effective storage capacity is 11.62 million tons. The study showed that the carrying out pilot CO₂ geological storage projects in small- and medium-sized sedimentary basins can alleviate the pressure of carbon emissions from the coastal areas and enterprises to a certain extent. At the same time, it can accumulate technology and experience for marine geological carbon storage.