The Potential Effect of CO2-Water-Rock Reaction on The Caprock Formation (<i>Mudstone</i>) Case Study

Abstract

By using a 1D column geometrical model this paper carried out research on the effects of CO2 penetration on the caprock properties. The result show that due to CO2 ingression the formation water environment changed greatly. The pH reduced to 3.8 from initial 7.48 and then buffered to 5.6; The supercritical CO2 reached to 0.006 m in the caprock, but aqueous CO2 reached to 1.1 m. The self-sealing efficiency worked after about 25 years, and the relevant minerals were calcite, quartz, kaolinite and calcite. The research will provide some technical reference for site selection of CO2 geological storage projects and CO2 leakage assessment.