How to Include the Capillary Number in Gas Condensate Relative Permeability Functions?

Abstract

Abstract The important role of near-miscible relative permeability functions in the formation of a retrograde condensate zone around the well bore is well established. The functions depend on the ratio of viscous to capillary forces on a pore scale, denoted by the capillary number. A large number of methods have been proposed for including the capillary number in the gas condensate relative permeability functions. We have reviewed and analyzed fifteen different methods. These can be divided into two classes:using Corey functions in which the Corey coefficients are interpolated between immiscible and miscible limits, andinterpolation between integral immiscible and miscible relative permeability curves. In both methods the interpolation is weighted by capillary number dependent functions. From the reviewed methods we have distilled three different weighting functions that are most suitable. We have calibrated the correlations to four experimental data sets. As the capillary number we have used. The results show that the weighting function proposed by Whitson and Fevang is the most convenient; this function covers the entire range of capillary numbers, and is able to reproduce the most important aspects of the dependence of relative permeability on the capillary number with a limited number of parameters. The function can be used for the interpolation of Corey coefficients as well as of integral relative permeability curves. P. 661