Simulation of O/W Emulsion Flow in Alkaline/Surfactant Flood for Heavy Oil Recovery

Abstract

Summary The formation and flow of emulsions during alkaline flooding process plays an important role for improving heavy oil recovery. In this study alkaline/surfactant (A/S) flood tests were performed in sandpacks to demonstrate the effectiveness of sweep efficiency improvement by the in-situ generated oil-in-water (O/W) emulsion. High tertiary oil recoveries were obtained in sandpack flood tests. Experimental results were history matched by including the mechanisms of in-situ generation and flow of O/W emulsion, as well as the chemical adsorption and the reduction of interfacial tension involved in the chemical flooding process. The decrease in local water phase permeability caused by the entrapment of emulsion droplets was modelled using the filtration theory. Both the pressure response and the oil recovery improvement were fairly matched. Field-scale simulations were conducted to investigate the potential of A/S flooding for heavy oil reservoirs. Simulations showed promising results of chemical flooding for heavy oils. It was indicated that a certain length of waterflooding time would benefit the final oil recovery, and there existed an optimum chemical slug size. These laboratory results and the simulation technique are helpful in the simulation and design of field-scale projects of chemical flooding for enhanced heavy oil recovery.