Progress and prospects of CO₂ geological storage in saline aquifer

The Paris Agreement signed by numerous countries around the world at the Climate Change Conference have provided new ideas for carbon emissions and temperature control in response to global warming. The Carbon Capture, Utilization, and Storage (CCUS) is one of the strategies for dealing with excessive CO₂ emissions. As one of the CO₂ storage methods, saline aquifer storage is characterized by wide reservoir distribution, good matching with carbon emission sources, large storage potential, and low environmental impact. Four main mechanisms of saline aquifer storage, including structural, capillary, dissolution, and mineralization storage were reviewed, and four main controlling factors of capping layer, physical parameters of reservoir, CO₂ purity, and storage operation were focused. In addition, the cases of global saline aquifer CO₂ storage projects were introduced, and the suitable CO₂ storage methods were summarized after analyzing and comparing the geological and tectonic backgrounds of the global saline aquifer storage projects, the storage processes, the potentials and the environmental monitoring methods, and so on. At last, suitable sites for CO₂ storage and the appropriate monitoring mechanism, with a view to providing references for the geological storage of CO₂ in saline aquifer in China were synopsized and prospected.