Numerical Simulation of Component Transfer and Oil Drive of Nonalkali Ternary Emulsion Systems

So far, alkali/surfactant/polymer flooding is widely used in oilfields to improve recovery. However, the introduction of alkali to the ternary composite leads to substantial damage formation, accelerates the scaling and corrosion loss in all aspects of surface injection and recovery, and consequently increases the cost of oil recovery in the ternary composite drive field. Therefore, environmentally friendly means are in urgent demand. Alternatively, a new non-alkali ternary drive system with salt instead of alkali has been developed based on the basis of ternary composite drive in the Daqing oilfield. In this experiment, a mathematical model of oil repelling by a salt-substituted alkali-free ternary emulsion system is formed, followed by the verification of the wet-lab experiments. The results show that the alkali-free ternary emulsion system can have a synergistic effect of complex salt and petroleum sulfonate surfactant and represents a wide range of ultralow interfacial tensions and good oil-repelling performances. The chromatographic separation occurs in the transmission process due to the adsorption of porous media, and the lower the permeability and the lower the injection rate, the higher the chromatographic separation degree. The use of multistage plug injection can narrow the difference of flow rate between high and low permeability layers and improve the recovery rate to 61.59%. Herein, the results provide theoretical guidance for the application of an alkali-free ternary emulsification system.