Effect of alkaline materials on interfacial rheological properties of oil-water systems

Interfacial rheological properties of a model crude oil-water system were s tudied in the presence of sodium hydroxide. The interfacial viscosity, the non-Newtonian flow behavior and the activation energy of viscous flow were determined as a function of shear rate, alkali concentration and aging time . The fundamental conclusion of the experimental results is that the interf acial viscosity drastically decreases in the presence of alkaline materials and the change under favorable conditions may exceed 3 or 3 orders of magn itude. Simultaneously, the sodium hydroxide effectively suppresses the non- Newtonian flow behavior of the interfacial layer. The experimental observat ions are explained by simultaneous chemical processes taking place in the b oundary layer. The present data may help to elucidate the formation, stabil ity and breaking of alkali-containing oil-water emulsions and they provide additional information for better understanding of the displacement mechani sm and for the formulation of alkaline flooding as a potential chemically e nhanced oil-recovery method.