Fines migration and mineral reactions as a mechanism for CO2 residual trapping during CO2 sequestration

Evolution of Bentheimer Sandstone Wettability During Cyclic scCO2‐Brine Injections

“…Ge et al. (2022) reported that fines migration (induced via original saturation with CO 2 ‐saturated water) increased residual saturation of scCO 2 relative to core flooding experiments where fines migration is unlikely to occur (i.e., cores originally saturated with water not equilibrated with scCO 2 ); the authors of that study attributed the elevated trapping to pore throat blockage by fines. We note that the original saturating fluid (unsaturated vs. saturated with scCO 2 ) would also likely impact whether adhesion might occur.…”

“…Ge et al (2020) and Zhang et al (2020) suggest that a primary impact of fines migration is the mobilization of fines and subsequent blockage of pore throats, leading to reduced permeability. In a more recent study, Ge et al (2022) also found that fines migration increased residual saturation of scCO 2 ; the authors attribute this effect also to pore throat blockage. Even in the absence of fines migration, the wettability of clay minerals can have a significant impact on relative permeability endpoints and subsequent trapping of scCO 2 (Fan et al, 2020).…”

Effects of different mineral reaction kinetics equations on predicting long‐term CO 2 mineral sequestration

“…(Δ r G) in Figure 3A, so the value of f TST (Δ r G) of the K-feldspar in case 1 is more susceptive to the change of Δ r G than other cases. The Δ r G value in Figure 3 are substituted into Equations ( 3), (5), and (7) to calculate that the crest value of the K-feldspar f TST (Δ r G) in the reaction range is close to 1 in case 1, while the crest value in the other four schemes was 0.80, 0.62, 0.61, and 0.42, respectively, accounting for 60% of the results of case 1 on average. If we take a global view of the entire 10 000 years of simulation, the percentage shrinks further to less than 20%.…”

“…It is one of the important means to reduce greenhouse gas emissions effectively to capture CO 2 generated by industrial activities and inject it into underground deep saline aquifers for storage 6,7 . A series of gas‐water‐rock interactions will occur after CO 2 is injected into a saline aquifer, and these interactions include both physical and chemical processes.…”

“…5 It is one of the important means to reduce greenhouse gas emissions effectively to capture CO 2 generated by industrial activities and inject it into underground deep saline aquifers for storage. 6,7 A series of gas-water-rock interactions will occur after CO 2 is injected into a saline aquifer, and these interactions include both physical and chemical processes. Finally, CO 2 is sequestered in the saltwater layer for a long time through the following four mechanisms: (1) structural trapping; (2) residual CO 2 trapping; (3) solubility trapping; and (4) mineral trapping.…”