Mechanisms of the displacement of one fluid by another in a network of capillary ducts

The mechanisms of displacement of one fluid by another are investigated in an etched network. Experiments show that both fluids are simultaneously present in a duct, the wetting fluid remaining in the extreme corners of the cross-section. Calculation of displacement pressures are in good agreement with experiments for drainage, imbibition and removal of blobs. The results may be related to some flow behaviour exhibited in porous media.