Effects of Long-Term CO₂ Storage on Carbonate Rock Stability

Carbon geostorage (CGS) is a proven technique for reducing anthropogenic CO₂ emissions and mitigating global warming by injecting CO₂ into deep geologic formations like saline aquifers or reservoirs. However, long-term exposure to CO₂-rich brine can alter the petrophysical properties and impact the storage integrity. This study examines the impact of CO₂ sequestration on the limestone core sample integrity, focusing on porosity, wormhole formation, and geometric tortuosity. Four limestone samples of 1.5-in. in diameter and 3-in. in length were aged in live brine at 60 °C and 2000 psi for 60 days to simulate sequestration conditions. Results showed a uniform increase in porosity, minimal wormhole formation with negligible impact on rock integrity, and increased geometric tortuosity, adding pathway complexity without compromising structural stability. These findings confirm limestone’s suitability for long-term CO₂ storage.