Dissolution of CO2 into brine forms a mixture that is denser than the ambient brine. The density gradient causes gravitational instability and triggers convective fingers, which is a favorable process for CO2 sequestration in saline aquifers. A series experiments of density driven natural convection due to CO2 dissolution were conducted in a transparent vertical Hele Shaw cell under different conditions. A spectrophotometric method for measuring the concentration of dissolved CO2 using an acid-base color indicator. The visualization of CO2 dissolving into brine process demonstrated that the onset time of fingers occurrence was too short to captured. Our results showed that higher pressure and temperature can promote the fingers growth; Brine salinity increase inhibits fingers growth, thus decreasing the concentration of the dissolved CO2.
Keywords CO2 sequestration, visualization, natural convection, Hele-Shaw, density driven