Abstract: Understanding the material composition and pore structure variation of shale gas reservoirs during supercritical CO₂-shale interaction is of essence to achieve CO₂ sequestration and enhanced natural gas production. The storage space evolution associated with mineral corrosion has been well reported, but the studies on the secondary precipitation and plugging characteristics are still insufficient, and there is particularly a lack of theoretical and experimental investigations. To analyze mineralogical corrosion/precipitation characteristics and its effects on adsorption capacity with different reaction time (6‒30 days) and thus demonstrate the fluid-solid interface kinetics and evolution laws of pore structure, the supercritical CO₂ (scCO₂)-water-shale reaction, scanning electron mi-croscope (SEM), low-pressure N₂ adsorption and isothermal adsorption experiments were primarily conducted using the Lower Silurian Longmaxi shales in the southern Sichuan Basin. The results reveal that the content of calcium and potassium minerals in the sample after the reaction gradually decreases with time, leading to an increase of Ca²⁺ and K⁺ concentration in the solution. Calcite minerals are notably corroded across the reaction, accompanied by a number of carbonate precipitates that converge on the surface. Corrosion generally expands the initial pore space, resulting in a volumetric increase of pores ranging from 3.29 to 4.50 nm. But the precipitation process may lead to pore space plugging and correspondingly shrinks the increments of the pore volume. As a result of corrosion and precipitation, the surface fractal dimension D₁ increases slightly, while the structure fractal dimension D₂ shows a reducing trend, which intensifies pore heterogeneity. In general, mineralogical corrosion can enlarge the samples’ storage space, initiate more CO₂ molecules to be polarized, and thus strengthen interactions between scCO₂ fluids and shale. These are the main reasons for the enhancement of adsorption capacity and adsorption potential. There is no remarkable change in the adsorption and adsorption potential of the sample before and after precipitation, indicating that the precipitation effect has a minor impact on adsorption capacity. Insights into corrosion and precipitation mechanisms and their effects on storage space are a matter of enlightenment for high-efficiency and long-term CO₂ geo-sequestration.