A Comparison of Calculated krg/kro Ratios With a Correlation of Field Data

Abstract

Abstract It is shown that krg/kro ratios computed on the assumption that the average sandstone reservoir has a poresize distribution characterized by a linear 1/Pc2 saturation plot are in good agreement with corresponding krg/kro ratios obtained by Wahl, Mullins and Elfrink by the correlation of field measurements. Equation for Calculating krg/kro Ratios Methods of calculating relative permeability data have recently been reviewed and extended. It was shown that for sandstone reservoirs where 1/Pc2 is approximately a linear function of effective saturation (as suggested first by Corey) it is possible to express relative permeabilities in very simple terms. For systems wetted by connate water and producing oil and gas (gas saturation growing at the expense of oil) the expression for the krg/kro ratio is ....................(1) The accuracy of Eq. 1 has been frequently confirmed in our laboratories; because of its simplicity we make routine use of it in the analytical solution of problems in reservoir engineering. Nevertheless, comparisons of the krg/kro ratios yielded by Eq. 1 with appropriate reservoir data have been few. The publication by Wahl, Mullins and Elfrink of an empirical equation for krg/kro ratios is thus of interest since this equation is specifically stated to be based on the correlation of field measurements made on sandstone reservoirs.