Influence of aqueous phase volume fraction, organoclay concentration and pressure on invert-emulsion oil muds rheology

This paper studies the effect that both aqueous phase fraction and organoclay concentration exert on the rheological properties of model suspoemulsions under pressure, commonly used in the formulation of invert oil muds for the drilling industry. These emulsions show a complex rheological behaviour that follows the Herschel–Bulkley's model. The yield stress shows a linear dependence with internal aqueous phase fraction for emulsions formulated with low organoclay concentration and power-law dependence for higher concentration. Barus’ model fits the pressure dependence of suspoemulsion viscosity, for different disperse phase volume fractions and organoclay concentration, fairly well.