Abstract
In this paper, the Johansen formation in the Norwegian CO2 geologic sequestration project is taken as the research object, and a multi-field coupled chemical-seepage-stress model is established to analyze the effects of CO2-water-rock reaction on the mechanical structural parameters, such as the pore pressure and the effective stress. Tensile safety factor and shear safety factor of the caprock are selected as evaluation indexes to describe the evolution of the caprock mechanical sealing ability over time dynamically. The simulation results show that the mechanical parameters change a lot during 0-50 years, and the change of mechanical parameters near the injection wells is larger than that far away from the injection wells, indicating that mechanical damage is more likely to occur near the injection wells. However, in 200 years, the tensile safety factor and shear safety factor of the caprock are always greater than 0, indicating that no tensile damage or shear damage occurs in the caprock, and the caprock sealing ability is good.
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