Experimental investigation of the impact of rock dissolution on carbonate rock properties in the presence of carbonated water

Carbon dioxide (CO2) storage in aquifers or injection to petroleum reservoirs for enhanced oil recovery purposes are the ways of mitigation of global warming. Dissolution of carbon dioxide in water forms carbonic acid. This acid would react with the carbonate components in carbonate rocks (i.e., CaCO3, MgCO3) and cause dissolution of salts thereafter changing carbonate rocks intrinsic properties. Dissolution changes the properties of carbonate rocks. To investigate these phenomena, two carbonate rock samples were saturated with brine and brought in contact with carbonated water for about 12 days. After each 72-h period, porosity, permeability, the mass of the cores and concentration of released ions in brine were measured. Concentrations of released ions were calculated by titration in each period. A considerable change on rock properties was observed. Porosity and permeability changes were about +8.09 and ±9.73 %, respectively, and core weight loss was about 0.82 Wt %. Besides, intensity of the concentration of released magnesium ions in brine with comparison to calcium ions indicates that the core samples are dolomite. The results of this study show that carbonate rock dissolution should be considered in water alternative CO2 injection, carbonated water injection and CO2 storage projects.