Nonequilibrium adsorption of surfactants onto reservoir cores from the North Sea. The effects of oil and clay minerals

Nonequilibrium adsorption of ethoxylated surfactants, mixtures of sulfonates and nonionic alcohoIs, onto two North Sea reservoir sandstone eores has been studied at reservoir temperature. One of the cores was cleaned prior to the adsorption studies, and the other core contained residual oil saturation, thus maintaining the reservoir wettability. The adsorption was followed by circulating the surfaetant solution through the cores for several months (1700 PV), using synthetic sea water.