Abstract
Increasing atmospheric CO 2 levels call for secure, large-scale storage methods, and deep brine reservoirs represent the most widely available and scalable option. However, accurately predicting long-term CO 2 dissolution in these systems remains challenging and difficult because of the complex chemistry of temperature, heterogeneity, capillary forces, and geochemical reactions. This research employs advanced numerical simulations to evaluate these effects on the dissolution of CO 2 in heterogeneous, finite saline aquifers. A key novelty is the integration of experimentally derived diffusion coefficients, extended to higher temperatures via Arrhenius-based predictions, into the CMG simulator, thereby strengthening the linkage between laboratory data and reservoir-scale modeling. The simulations examine CO 2 dissolution across a wide temperature range (35–100 °C) while systematically evaluating the roles of capillary forces, aquifer heterogeneity, salinity, brine density evolution, and mineral–fluid reactions on plume morphology and trapping. To reduce computational complexity, three representative temperature levels (low, medium, and high ranges) were selected for the sensitivity analysis. Results reveal that at 35 °C, capillary forces enhance CO 2 dissolution efficiency by roughly 7%, driven by lower molecular kinetic energy and stronger interfacial interactions within confined pore spaces. Nonetheless, this effect diminishes at 100 °C due to the increased molecular energy and lower interfacial tension. Without geochemical interactions, dissolution efficiency increases by roughly 20% with temperature, from 45% at 35 °C to 70% at 100 °C. With geochemistry considered, redistribution of dissolved CO 2 into ionic and mineral-associated species reduces the apparent efficiency to around 36 and 47% at 35 and 100 °C, respectively. Finally, the findings demonstrate the necessity of accurate diffusion parametrization and the coupled consideration of temperature, capillary forces, geochemistry, and heterogeneity for predicting long-term CO 2 dissolution and trapping in deep saline aquifers.