Geochemical Impacts of SO2 Impurity Concentration on CO2 Storage

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🔬研究者:Provides detailed geochemical data on SO2-CO2-rock interactions under controlled conditions, useful for modeling and risk assessment of CCS.

🏢実務担当者:Highlights that even low SO2 levels can alter reservoir properties; important for gas quality specifications and injection planning in CCS projects.

Carbon capture and storage (CCS) is a promising technology for reducing atmospheric CO2 emissions from major industrial sources. The consideration of storing impure CO2 streams has increased, as the high cost of CO2 capture and purification remains a key barrier to large-scale CCS deployment. However, impurities such as SOₓ can significantly influence reservoir geochemistry and fluid–rock interactions. Among these, sulfur dioxide (SO2) is particularly reactive and can intensify geochemical processes even at low concentrations. This study investigates the geochemical and petrophysical impacts of SO2-contaminated CO2 on clastic reservoir rock under controlled laboratory conditions. Core samples were exposed for 30 days to pure CO2, CO2–0.1% SO2, and CO2–0.4% SO2 systems in an aging cell. Integrated analyses were conducted to evaluate mineralogical evolution and pore structure modification. Results indicate that rock–fluid interaction is dominated by acid-driven dissolution, with reaction intensity increasing systematically with SO2 concentration. FESEM observations revealed grain surface etching, pore enlargement, and localized mineral removal. XRD analysis confirmed progressive reduction of albite and microcline, supported by effluent chemistry showing elevated ion concentrations consistent with enhanced mineral dissolution under stronger acidity. Porosity generally increased due to mineral dissolution, while permeability exhibited a non-linear response reflecting competing mechanisms of pore generation and localized pore blockage. At 0.4% SO2, FESEM–EDX identified NaCl precipitation within pore spaces, indicating potential injectivity impairment at higher impurity levels. Overall, the findings demonstrate that even low SO2 concentrations significantly accelerate geochemical reactions and alter reservoir properties. While dissolution may enhance pore development, higher impurity levels introduce risks of salt precipitation and permeability variability. These results highlight the importance of understanding impurity-driven geochemical processes for reliable assessment and management of CO2 storage systems.

• semanticscholar https://doi.org/10.2118/233307-msfirst seen 2026-07-04 05:31:20