EFFECTS OF PORE STRUCTURE ON DISPLACEMENT EFFICIENCY IN RESERVOIR ROCKS AND IN GLASS MICROMODELS.

In strongly wetted reservoir rocks, the extent of nonwetting phase trapping is strongly dependent on the geometric and topologic properties of the pore system. It has been demonstrated that pore-throat size ratio and certain types of heterogeneity affect displacement efficiency adversely. Throat to pore coordination number or connectivity and the condition or roughness of pore surfaces are important factors affecting displacement efficiency. Under conditions of intermediate wetting, pore geometry appears to be of reduced significance as a cause of trapping and, under these conditions, displacement efficiency is greater.