Jiyue Wu

Basalt is a promising geological medium for CO₂ storage because of its potential for permanent mineral trapping, although fluid–rock reactions can alter pore structure and hydraulic properties. This study investigates coupled axial deformation, hydraulic and geochemical evolution of basalt during CO₂-saturated brine flow at 88 °C and approximately 210 bar pore pressure. In situ axial deformation, differential pressure and apparent permeability were monitored continuously, while effluent chemistry, mineral saturation states and pore-structure properties were evaluated. Six axial deformation stages were identified, with a pronounced hydraulic transition after approximately 115 pore volumes (PV) injected. Larger deformation magnitudes coincided with decreasing differential pressure and increasing apparent permeability, and absolute axial strain change was positively correlated with stage-averaged apparent permeability (r = 0.919, R² = 0.8437). Absolute permeability increased from 2.41 to 8.55 mD, while measured porosity increased only slightly from 9.15% to 9.51%. Fe and SiO₂ concentrations generally increased during reactive flow, and late-stage saturation indices indicated thermodynamic favorability for selected secondary phases. Nitrogen adsorption measurements showed changes in accessible pore structure. These results demonstrate concurrent deformation, hydraulic and geochemical evolution and indicate that permeability evolution cannot be explained by changes in bulk porosity alone.

Basalt is prevalent in the Earth’s crust and makes up about 90% of all volcanic rocks. The earth is warming at an alarming rate, and there is a search for a long-term solution to this problem. Geologic carbon storage in basalt offers an effective and durable solution for carbon dioxide sequestration. Basaltic rocks are widely used for road and building construction and insulation, soil amendment, and in carbon storage. There is a need to understand the parameters that affect this process in order to achieve efficient carbon mineralization. This review systematically analyzes peer-reviewed studies and project reports published over the past two decades to assess the mechanisms, effectiveness, and challenges of carbon mineralization in basaltic formations. Key factors such as mineral composition, pH, temperature and pressure are evaluated for their impact on mineral dissolution and carbonate precipitation kinetics. The presence of olivine and basaltic glass also accelerates cation release and carbonation rates. The review includes case studies from major field projects (e.g., CarbFix and Wallula) and laboratory experiments to illustrate how mineralization performs in different geological environments. It is essential to maximize mineralization kinetics while ensuring the formation of stable carbonate phases in order to achieve efficient and permanent carbon dioxide storage in basaltic rock.