An Overview and Evaluation of the Mechanistic Models for Wettability Change in Modified-Salinity Waterflooding in Carbonates

Abstract

Summary The mathematical attempts to model the modified salinity waterflooding (MSW) in carbonates complement the experimental studies and aim at bringing closer the implementation of this improved oil recovery (IOR) method at the field scale. Although multiple causes have been identified for the additional oil recovery during MSW, most modelling work only cover the wettability alteration mechanism. The current mechanistic models describe the shift in the wetting conditions upon injection of a chemically tuned brine composition by defining a parameter to interpolate between the relative permeability curves at water-wet and oil-wet conditions. In this work, we assess the correlation of several interpolants proposed in the literature with the remaining oil saturation from reported spontaneous imbibition tests carried out on chalk. The results show that, among the parameters studied, only the “available adsorption sites” parameter shows a trend and could therefore explain the additional oil recovery observed during MSW in chalk.