A modified Leverett J-function for the Dune and Yates carbonate fields: A case study

Effective medium theory (EMT) has been used to model capillary pressure (P- c) as a function of water saturation (S-w) in porous media. The EMT model r esults show that both the magnitude and profile of the P-c - S-w profile ar e strongly affected by changing the pore-size distribution parameters and t he rock pore geometry. Tortuosity, which is a function of these parameters, ; is used in developing a drainage capillary pressure model based on data f rom the Dune and Yates fields. Capillary pressure is normalized with respec t:to lan average pore radius that includes tortuosity. To minimize the unce rtainty caused by the contact angle term, only helium/water capillary press ure curves were considered. The:wetting-phase saturation is normalized with respect to an asymptotic irreducible wetting-phase saturation. For the Dun e and Yates fields, the development of this type of dimensionless model may be useful as an input for reservoir simulation studies.