Emulsion flooding for enhanced oil recovery: Filtration model and numerical simulation

The present paper discusses emulsion flooding laboratory experiments in porous media with the application of the Filtration Theory, and a series of simulation experiments that showed the potential use of emulsions as EOR technologies in Mexican mature fields with approximately 20° API gravity oil and high water cut production. This method is based on the hydrophobization of sandstone rocks and the reconfiguration of water flow patterns, by means of O/W emulsion injections, improving and increasing the oil recovery. Emulsion flooding laboratory experimental tests were performed with Ottawa sand and Berea sandstones. During the oil recovery process, the additional oil recovery was above 25%. The dispersed phase of the emulsion is retained at the pore throats, leading to porous medium impediments described by two mechanisms: (a) pore blockage by size exclusion, and (b) drop retention due to interactions between droplets and pore walls. Both mechanisms cause irreversible permeability reduction. In order to know the general effect on this process, a filtration model describing emulsion flow through porous media was used to obtain filtration parameters. In our work, we describe the use of a well-known mathematical model, which consists of a differential equation system based on the Filtration Theory and a modified Darcy equation that is characterized by three parameters: filter coefficient, flow redistribution and local flow restriction factors. The EOR simulation model by emulsion flooding was created using STARS™ by CMG. The conceptual mathematical model and fitting of the experimental results concerning the oil displacement by water and additional oil displaced by the emulsion show that the wettability change caused by the emulsion is the main recovery mechanism.