A synergistic approach to CO2 sequestration: evaluating trapping mechanisms in saline aquifers

Rising fossil fuel consumption intensifies CO2 emissions, worsening climate change. Carbon Capture and Storage (CCS) technologies offer a promising solution by securely storing CO2 in geological formations, mitigating environmental impacts. This paper presents a long-term synergistic study of multiple CO2 trapping mechanisms in saline aquifers over 200 years and represents a key knowledge gap in the existing literature on CCS. The research was done with advanced numerical modeling using the CMG-GEM software and integrated all the structural, residual, solubility, and mineral trapping mechanisms to find their integrated effect on the efficiency of CO2 storage. These results show that combined dissolution and mineral trapping increase the storage capacity by about 27 %, equivalent to a 400 % increase over the no-dissolution, no-trapping base case. By integrating these methods, a clearer understanding of the interrelations between various trapping mechanisms was obtained, and an effective tool for optimizing strategies in the sequestration of CO2. The complete uncertainty analysis using Monte Carlo simulations for the variability in main input parameters like porosity, permeability, and mineralogical composition is of special note. The approach quantifies the uncertainty over the range of possible results by providing confidence intervals of capacity estimates, enhancing the reliability and broader applicability of the outcomes. This research underlines the long-term stability, environmental safety, and uncertainty quantification of geological CO2 storage; therefore, it provides practical implications for the design and implementation of CCS projects. This research contributes significantly to climate change mitigation by providing necessary guidance for policymakers and engineers to develop appropriate technology for secure and sustainable CO2 storage by illustrating the advantages of a multi-mechanistic approach and discussing issues about uncertainties.