WETTABILITY EFFECTS ON SCALING 2-FLUID AND 3-FLUID CAPILLARY PRESSURE-SATURATION RELATIONS

Capillary pressure (P-c) - saturation (S) relationships for porous med ia containing three fluids are often predicted from two-fluid P-c-S cu rves. This practice was investigated for porous media with different w ettabilities. Two- and three-fluid P-c-S curves were measured, using a n automated setup, for sands containing air and water; air and oil, oi l and water, and air, oil, and water. Similar P-c-S curves were found for air-oil systems while differences occurred for air-water or oil-wa ter due to differences in hydrophobicity and contact angle hysteresis, Three-fluid P-c-S curves could be accurately predicted for hydrophili c media from two-fluid P-c-S data with scaling, using fitted contact a ngles and measured interfacial tensions, and Leverett's assumption. Su ch predictions were found to be inadequate for hydrophobic media becau se the intermediate fluid is presumably discontinuous.