Unified Capillary Pressure saturation Relationship in Porous Media Two phase Flow

The movement of Non aqueous Phase Liquids (NAPLs)(usually organic compounds) in subsurface porous media is a problem of multiphase flow. Prior to solving governing equations of multiphase flow, the capillary pressure saturation relationships of different multiphase must be set up. Based on previous research, it is understood that for any porous media it is possible to get an unified capillary pressure saturation relationship for arbitrary two phase flow, and the problem is how to estimate the scaling coefficients of capillary pressure. Using capillary rube model of porous media,scaling coefficients of capillary pressure are deduced in this paper. The results show that the scaling coefficients, in the same porous medium, if any pair of two phase (usually air water two phase system is selected as the reference) capillary saturation relationship is known, then the other two phase (air NAPL and NAPL water) capillary saturation relationships can be obtained too.