Effects of Interfacial Tension and Droplet Size on the Plugging Performance of Oil-in-Water Emulsions in Porous Media

Abstract

Property tests were first conducted to characterize the subject oil-in-water emulsions having three different interfacial tensions and three different droplet sizes in terms of their stability, droplet size distribution, and rheological behaviors. Then sandpack flow experiments were conducted, and permeability reduction tests were used to quantify the plugging performance of each of the different emulsions flowing at different flow rates through sandpacks. The results showed that the plugging effect of an oil-in-water emulsion was primarily due to the special flow behaviors of emulsion droplets in porous media; that is, the bulk viscosity of an emulsion contributed very little to the plugging effect. This paper has shown, for the first time, a correlation of emulsion plugging ability and interfacial tension. Permeability reduction of oil-in-water emulsions in sandpacks increased with an increase in interfacial tension and droplet size. At a fixed flow rate, emulsions with σ = 5.2 mN/m and σ = 9.3 mN/m had...