Abstract: The systems and method described in this specification relate to a method for determining a residual oil saturation of a reservoir. The method includes obtaining a plurality of rock samples from the reservoir; determining a permeability of each of the rock samples; measuring a fluid viscosity of oil in the reservoir; estimating a location-specific permeability of the reservoir across the reservoir based on the permeability of each of the rock samples; determining a location-specific displacing velocity of the reservoir based on a function of the location-specific permeability and the fluid viscosity of the oil; determining the residual oil saturation of the reservoir based on the location-specific displacing velocity using Franklin's equation; and predicting a recovery of the oil from the reservoir using the residual oil saturation in a computational model of the reservoir.