Visualization of water/oil displacement in porous media in the presence of chemical reaction.

Abstract

In enhanced oil recovery, low interfacial tension, optimum wettability condition, high pH value, and the electric charge density at the interface can improve the oil recovery percentage appreciably. However, the addition of sodium hydroxide changes the interfacial tension to an ultra-low value. Interfacial tension decreases as a result of the interfacial reaction between the surface active species in the oleic phase and the caustic in the aqueous phase. The surface active species also provide favorable wettability conditions and interfacial activity which improves the recovery percentage. This study has investigated the effects of caustic concentration in the aqueous phase on the recovery percentage, and on the displacement pattern in a radial cell. The caustic solutions were employed as the displacing phase being brought into contact with the acidic oil in the cell. The displacing aqueous phase contained different concentrations of sodium hydroxide ranging from 0.0 mM to 25 mM, and the displaced phase was a light paraffin oil containing 10 mM linoleic acid. In this research, the effect of flowrate on oil recovery percentage was also examined. (Abstract shortened by UMI.)