Capillary pressure-saturation relations in porous media including the effect of wettability

In this work a functional relationship between capillary pressure and wetting phase saturation has been developed. Both the imbibition and drainage of a wetting phase liquid into a porous medium consisting of clean unconsolidated silica particles have been considered. In all, two bead packings, with average particle diameters of 120 #m and 360 #In, and three liquids--water, ethanol, and refrigerant-113--were studied. It was found that the Leverett function worked very well in describing the relation between capillary pressure and saturation for each liquid using both packings; however, it did not provide adequate correlation for all three liquids. The functional relationship presented here considers the dependence of capillary pressure upon the contact angle of the fluid-solid interface, and also conveys how this dependence varies with saturation. The inclusion of the contact angle dependence provides extension of the correlation to any wetting phase liquid of uniform properties.