Pore-scale mass transfer experiments in porous media by X-ray CT scanning

Understanding the physical trapping mechanisms is important to design successful CO2 storage projects. Among major trapping mechanism, the dissolution trapping is mainly influenced by the mass transfer between CO2 and brine interface. A typical dimensionless number, the Sherwood number, is predicted as empirical formulas with the CO2 volume fraction and the Reynolds number. Experiments of brine imbibition into pores which are occupied by CO2 are performed with different Re and injection direction. The most active mass transfer region are consist of relative high Re and high CO2 volume fraction according to the fitting results, and the Sh decrease intensely when Re decrease, especially when Re is below 0.1. Also the descending CO2 volume fraction have relative slight impact on Sh, inducing a probably decline of values. Thus for brine in aquifers a higher migration velocity when imbibition process will accelerate the dissolution process and be benefit to the safety of reservoir. (C) 2016 The Authors. Published Elsevier Ltd.