This study reviews subsurface microbial activity, biomineralization reactions, and the mechanisms prevalent for bioremediation of wells, stabilization of cements, and increase in CO2 trapping and leakage reduction during CO2 injection and storage. Laboratory studies have revealed that microbial growth under supercritical CO2 conditions is challenged by acidic brine pH and elevated CO2 partial pressures. However, the presence of minerals such as calcite, dolomite, feldspars, and clay minerals can buffer these stresses and sustain microbial communities to enable biofilm formation and bioprecipitation of carbonate minerals to increase CO2 trapping in the reservoir.
Biogeochemical Effect of CO2 Injection
Subsurface formations naturally host diverse microbial communities that can respond to CO2 injection. Microbial processes can influence storage performance by contributing to injectivity reduction, mineral precipitation, and microbially influenced corrosion (MIC). Microorganisms can affect CO2 injection and storage in the four following ways:
Biofilm formation can alter flow and storage
Microbially enhanced geochemical reactions can promote biomineralization
Carbonate minerals can be dissolved through acid production
Metals can be mobilized through redox reactions
Laboratory studies show that high CO2 pressures generally decrease microbial viability.
