Evaluation of CO2 solubility-trapping and mineral-trapping in microbial-mediated CO2–brine–sandstone interaction

Abstract Evaluation of CO 2 solubility-trapping and mineral-trapping by microbial-mediated process was investigated by lab experiments in this study. The results verified that microbes could adapt and keep relatively high activity under extreme subsurface environment (pH   50 °C, salinity > 1.0 mol/L). When microbes mediated in the CO 2 –brine–sandstone interaction, the CO 2 solubility-trapping was enhanced. The more biomass of microbe added, the more amount of CO 2 dissolved and trapped into the water. Consequently, the corrosion of feldspars and clay minerals such as chlorite was improved in relative short-term CO 2 –brine–sandstone interaction, providing a favorable condition for CO 2 mineral-trapping. Through SEM images and EDS analyses, secondary minerals such as transition-state calcite and crystal siderite were observed, further indicating that the microbes played a positive role in CO 2 mineral trapping. As such, bioaugmentation of indigenous microbes would be a promising technology to enhance the CO 2 capture and storage in such deep saline aquifer like Erdos, China.