DYNAMICS OF EMULSIFICATION AND DEMULSIFICATION OF WATER-IN-CRUDE OIL-EMULSIONS

The effect of aging on the crude oil/water interface has been studied, and the slow buildup of natural surfactants present in the crude oil at the interface was observed. Interfacial tension data and microvideo graphy were used to evaluate the buildup of surface concentration. The methodology adopted in this work permits the calculation of the actua l surface excess of natural surfactants at the crude oil/water interfa ce, without having to isolate them from the crude oil and without know ing their bulk molar concentration. The rate of adsorption of demulsif ier at the interface was determined by measurement of the dynamic inte rfacial tension by a microprocessor-controlled drop volume method appa ratus. Temperature, concentration, and nature of the medium (crude oil or brine) were found to be very important parameters governing adsorp tion of demulsifier at the interface. Diffusion of the emulsifier to t he oil/water interface was much slower when demulsifier was present in the oil phase than when it was present in the water phase.