Numerical Simulation on CO2 Dissolution into Aquifers =

As the world remains heavily reliant on fossil fuels as its primary energy source, a deepening concern has emerged regarding the release of human-generated carbon dioxide into the atmosphere. These emissions contribute significantly to the ongoing challenge of global warming. An extensively recognized approach to address the challenge of carbon dioxide emissions is the capture and underground storage of carbon within geological formations. This method entails the extraction of carbon dioxide from various sources and its secure sequestration underground, thereby preventing its release into the atmosphere. Carbon capture and storage (CCS) offers the potential to continue utilizing fossil fuels while concurrently reducing CO2 emissions by a substantial margin, up to 20%. The adoption of CCS may indeed emerge as a pivotal instrument in the pursuit of the global objective to restrict temperature increases to 2 °C. Upon the injection of CO2 into subsurface aquifers, various trapping mechanisms play a crucial role in preventing CO2 leakage to the surface, ensuring secure sequestration. Among these mechanisms, dissolution trapping falls within the chemical trapping category, driven by the density difference between CO2 and the brine in the formation. Molecular diffusion and convective mixing are the primary mechanisms that influence the dissolution rate. The timing of the start of dissolution and the point at which CO2 achieves its maximal dissolution level in brine is critical, as free CO2 can leak into the atmosphere through both caprock and wellbores during this important period. This research explores the dissolution of CO2 in a real system at laboratory scale and highlights the existing challenges, restrictions and some potential solutions to the challenges.