Scaling fluid content-pressure relations of different fluid systems in porous media

Two-fluid-phase relations among fluid saturations (S) and pressures (P) have historically been used to predict S-P relations for three-fluid-phase systems consisting of a gas, nonaqueous phase liquid (NAPL), and water, because measurements of three-phase S-P relations are complex. Two-phase S-P relations of air-NAPL systems are generally used to predict the behavior between total-liquid saturations of three-phase systems and air-NAPL capillary pressures. Two-phase S-P relations of NAPL-water systems are generally used to predict the behavior between water saturations of three-phase systems and NAPL-water capillary pressures. Because S-P measurements are very time-consuming, investigators have attempted to scale S-P relations so that fewer measurements would be required. A S-P scaling technique is discussed in this paper, and methods to predict the scaling factors are evaluated.