Flow of Emulsions in Porous Media

Abstract

Abstract Flow of emulsion in porous media plays an important role in many enhanced oil recovery processes. Drops may partially block pore passages leading to a better sweep of the reservoir. Despite all the efforts, the detailed mechanism of how emulsions flow through the pore space is not completely understood. Modeling the flow of emulsion in porous media is extremely challenging. In many situations the size of the dispersed phase drops is in the same order of magnitude of the pore throats. Therefore, in the pore scale the emulsion cannot be described as a single phase liquid with an effective viscosity. In this work we analyze the flow of emulsion in porous media by experiments and a capillary network model. The model is based on the flow rate-pressure drop relation of emulsion flow through constricted capillaries, which is a function of the capillary number of the flow, liquid properties and the ratio of drop to capillary throat diameter. The capillary network modeling was constructed in order to obtain macroscopic parameters from microscopic flow behavior. The results show how the permeability changes with Darcy velocity. At low flow rates, the large drops partially block the smallest pores, leading to a low permeability. At high flow rates, the pressure gradient in each capillary is strong enough to force the drops to flow through the constrictions. Consequently, the permeability rises with capillary number. The results agree well to experimental measurements in sandstone cores.