The Impact of Indigenous Microorganisms on the Mineral Corrosion and Mineral Trapping in the SO2 Co-injected CO2-Saline-Sandstone Interaction

摘要

The impact of indigenous microorganisms on the mineral corrosion and mineral trapping in the SO2 co-injected CO2-saline-sandstone interaction was investigated in this study by lab experiments under 55 degrees C, 15 M pa. The results verified that co-injection of SO2 resulted in a decrease in biomass and shifts in microbial communities within 90 days, but some microorganisms still could adapt to acidic, high-temperature, high-pressure, and high-salinity environments. Firmicutes and Proteobacteria remained dominant phylum, but phylum Proteobacteria showed better tolerance to the co-injection of SO2 in the initial period. In the SO2 co-injected CO2-saline-sandstone interaction under microbial mediation, acid-producing bacteria further promoted the corrosion of K-feldspar, albite, and clay minerals, meanwhile mobilizing more K+, Na+, Ca2+, Mg2+ into solution. The acidogenic effect may be linked to the dominant genus of Bacillus, Paenibacillus, Acinetobacter, Pseudomonas and Exiguobacterium. Co-injection of SO2 inhibited the carbonates capture, while microbial acid production further reduced the pH, further inhibiting carbonates capture. As a result, no secondary carbonate (e.g., calcite) was observed on a short time scale within 90 days. So, microbial acidogenic effect was not conducive to carbonates capture in short term.