EFFECTS OF OIL PHASE VISCOSITY ON INTERFACIAL-TENSION BEHAVIOR OF OIL ALKALINE SYSTEMS AS MEASURED BY THE SPINNING DROP TENSIOMETER

This note examines the effects of oil phase viscosity on the interfacial tension of reacting systems (acidic crude oils in contact with alkaline solutions) as measured by the Spinning Drop Tensiometer. Surfactants are produced by chemical reactions at the interface, thereby causing the shape of the oil droplet in the tensiometer to change continuously. The rates of droplet elongation/contraction are necessarily influenced by the oil phase viscosity, thereby affecting directly the measured interfacial tension. The principal conclusion of this work is that although oil phase viscosity exerts a significant effect on the dynamic interfacial tension after attainment of the minimum value, it makes for only a small absolute change in the magnitude of the minimum interfacial tension itself.