A model for the flow of emulsion in porous media with micro-heterogeneities

The flow of crude oil-water emulsion in porous media iscommon phenomena in the process of alkali-surfactant-polymer (ASP) floodingand thermal oil recovery. Microscopic structural characteristics of porousmedia show crucial effects on the flow of emulsion. Existing theoreticalmodels on the flow of emulsion in porous media are deterministic approachesto describe macroscopic volume-averaged performance of porous media withmicroscopic structures. There are inherent deviations between deterministicdescriptions and experimental results when smaller-scale heterogeneities cannot be omitted with the comparison of the size of porous media. In thispaper, a stochastic method on the flow of emulsion in porous media isdeveloped based on continuous time random walk (CTRW) formalism. Theprobability distribution functions of transition time and displacement ofdispersed-phase droplets give description of microscopic heterogeneities ofporous media. The results show that present model can effectively describethe scale-dependent long-tailed phenomena of experimental results and beused as general filtration model.