Three-dimensional imaging of multiphase flow in porous media

This paper reports progress in the 3D pore-scale micro-CT imaging of multiple fluid phases during drainage experiments in porous materials. Experiments performed on a sintered monodisperse bead pack and a Berea sandstone sample are described. It is observed that the residual (trapped) wetting phase in the sintered bead pack is present as pendular rings, bridges between adjacent grains and lenses within pore throats. Estimates of the residual wetting phase saturation are in accord with previous experiments and predictions on model bead packs. Relative permeabilities computed directly on the digitised images of the fluid phases are in good agreement with experimentally measured values for Berea sandstone. Two simple numerical methods for estimating two phase drainage saturation distributions directly from images are compared. Both methods give good agreement with the bead pack experiment. The match for Berea sandstone is poorer; differences may be due to variable wettability.