Recovery, recovery fraction and residual oil saturation correlations for sandstone, water-drive reservoirs

Abstract

A group of equations has been presented for predicting the recovery, recovery fraction and residual oil saturation of sandstone, water-drive reservoirs. Multiple-regression analyses have been used to develop these correlations. The equations presented vary in the number of variables considered and represent models which have been set forth describing the basic curvilinear relationships used for the analyses. Data collected by the Special Study Committee on Recovery Effiencies under the auspices of the American Petroleum Institute were used for the correlations. These data were supplied by numerous oil companies and included 57 sandstone, water-drive reservoirs located in Saudi Arabia, Venezuela, Canada and the United States. Pour equations are presented which yield the most accurate approximations of recovery and recovery fraction. The highest absolute average deviation of these equations was 17.1% and the lowest was 13.6%. One equation has been presented for the approximation of residual oil saturation which yielded an absolute average deviation of 10.8% between the observed and estimated values. This same correlation yields residual oil saturation values which, when used in an exact equation £or recovery, yield absolute average deviations of recovery of 12.1%.