Kinetics mechanism of pore pressure effect on CO₂-water-rock interactions: An experimental study

Carbon capture, utilization and storage (CCUS) is an effective technology to reduce carbon dioxide (CO 2 ) content in atmosphere, while due to the insufficient mastery of deterioration laws of reservoir rocks caused by CO 2 , the extensive application of carbon storage projects is hindered by the leakage risk. Therefore, it was aimed to study the kinetics mechanism of pore water pressure on CO 2 -water-rock interactions. First, the pressure effect on water-rock interactions was studied to obtain the relationship between ratio of solid-liquid contact area Psi and pore pressure, and the controlling mechanism of Psi on reaction rate r i was verified. On this basis, the pressure effect on CO 2 -water-rock interactions was further studied. Considering the effects on Psi and solution acidity, the original CO 2 -applicable kinetics equation was modified to reduce the error of calculating reaction rate by 33.60% on average. Meanwhile, a forecast method was proposed for the reaction rate under different pressure conditions, and the average calculation error was 41.00% lower than that of original kinetics equation. After verifying the accuracy of these two theoretical methods to calculate reaction rate, the reliability to calculate porosity evolution process was further verified, and the calculation errors could be reduced by 29.52% and 31.81%, respectively.