Influence of CO 2 solubilization conditions on dissolution and precipitation in carbonate matrices

Abstract High CO 2 concentrations in pre‐salt reservoir basins, combined with global efforts to reduce carbon emissions, underscore the need for enhanced oil recovery (EOR) techniques that maximize production while minimizing CO 2 release. Among these techniques, carbonated water injection (CWI) has gained increasing attention because it enables CO 2 utilization and geological storage during enhanced oil recovery while promoting the storage of dissolved CO 2 in geological formations. During CWI operations, the injection of CO 2 ‐enriched aqueous solutions can modify the physicochemical conditions of carbonate reservoirs, influencing dissolution and precipitation phenomena that affect fluid–rock interactions and potentially improve oil mobilization. This study quantifies the impact of key operational parameters and fluid properties on reactive processes in carbonate matrices. Flow‐through experiments were conducted on two carbonate samples with distinct textural and mineralogical attributes. The effects of CO 2 saturation temperature, outlet operating pressure, and carbonate mineralogy on fluid–rock interactions were systematically evaluated. Geochemical responses were characterized by evaluating the effluents (ionic speciation, pH and electrical conductivity) and solid‐phase alterations, assessed via X‐ray computed microtomography (μCT) and X‐ray diffraction (XRD). Results from a statistically designed experimental matrix indicate that CO 2 saturation temperature is the dominant factor controlling dissolution‐precipitation dynamics under the evaluated conditions (5°C–20°C and 60–100 bar), regardless of carbonate composition. These findings highlight the influence of CO 2 saturation temperature on the initial dissolved CO 2 concentration and brine‐rock reactivity during carbonated brine injection in carbonate reservoirs.