A Consideration on correlation equation between average saturaion and relative permeabilities

Abstract

This paper describes a relationship between average saturation and relative permeabilities of which values are estimated by using a probability density function of saturation. The authors have already proposed the estimation method and discussed the relative permeabilities in a porous medium with saturation distribution. In the result, the relative permeabilities depend not only on average saturation, but also on the standard deviation and the skewness. However, it is difficult to estimate their detail values in analyses of two-phase flow in a geothermal reservoir. In this paper, the relative permeability of gas-phase is calculated for each average saturation, each standard deviation, and each skewness, under an assumption that ralative permeability of liquidphase is proportional to second-or third-power of average saturation in a porous medium with saturation distribution. The calculations indicate the upper limit and the lower limit values of the relative permeability of gas-phase in the relation to the average saturation. Also, this paper proposes the approximation equations to express the relative permeabilities. These equations successfully describe effects of the saturation distribution on heat flow rate in a porous medium.