Percolation of supercritical CO2 in a porous medium saturated with water

We experimentally investigated the effect of capillarity and buoyancy on non-wetting phase saturation after the drainage. Distributions of the NWP in porous media have been visualized by mean of microtomograhy at a pore-scale for a supercritical CO2 and water system. In the case of the upward injection, gas saturation is low compared with the upward case, because the capillary fingering is enhanced by buoyancy. Gas saturation increases with the capillary number because of the pressure gradient along the porous medium. In the case of the downward injection, the fingering is suppressed by buoyancy. As a result, the high gas saturation is achieved over the wide range of capillary number. The gas saturation decrease slightly with the capillary number because of the instability associated with the injection flow rate. The combined dimensionless group of Bond number and capillary number is introduced to correlate with the gas saturation obtained for the nitrogen and water system. © 2013 The Japan Society of Mechanical Engineers.