Geochemical modeling and experimental evaluation of high-pH floods: Impact of Water-Rock interactions in sandstone

► We ran experiments in model and reservoir rocks to demonstrate buffering capacity of minerals. ► We demonstrate that anhydrite, among other minerals, regulates pH and ion profiles in floods. ► Geochemical model predicts well aqueous chemistry during oil recovery with alkaline solutions. ► Upscaling through modeling shows that lab results act as poor predictors of field chemistry.