Simulation of CO2-water-rock interactions on geologic CO2 sequestration under geological conditions of China

The main purpose of this study focused on the feasibility of geologic CO2 sequestration within the actual geological conditions of the first Carbon Capture and Storage (CCS) project in China. This study investigated CO2-water-rock interactions under simulated hydrothermal conditions via physicochemical analyses and scanning electron microscopy (SEM). Mass loss measurement and SEM showed that corrosion of feldspars, silica, and clay minerals increased with increasing temperature. Corrosion of sandstone samples in the CO2-containing fluid showed a positive correlation with temperature. During reaction at 70°C, 85°C, and 100°C, gibbsite (an intermediate mineral product) formed on the sample surface. This demonstrated mineral capture of CO2 and supported the feasibility of geologic CO2 sequestration. Chemical analyses suggested a dissolution-reprecipitation mechanism underlying the CO2-water-rock interactions. The results of this study suggested that mineral dissolution, new mineral precipitation, and carbonic acid formation-dissociation are closely interrelated in CO2-water-rock interactions.