Study On The Experiment And Seepage Mechanism Of Three Phase Foam Flooding After Binary Combination Flooding

Because of the bubble stabilization of solid particles,three-phase(gas,liquid and solid)foam flooding has more significant improvement in foam performance and stability than conventional two-phase(gas and liquid)foam flooding.Therefore,it has gradually become the new frontier and new direction of foam flooding research.In the conventional three-phase foam flooding system,spherical particles of nanometer or micrometer size are often adopted for the choice of solid particles.But the spherical silicon dioxide particles with nanometer or micrometer size are not ideal for the stabilization of three-phase foam in harsh environments such as high salinity,high temperature and strong acid-base environment.Therefore,the research and development of a new type of salt resistance,temperature resistance,acid resistance and alkali resistance three-phase foam agent has important and far-reaching significance.In this paper,the self-assembly effect of rodlike nanoparticles at the foam interface and the sliding effect of rodlike nanoparticles in the pore throat of formation have been studied.Based on the study of the mechanism of stable three-phase foam with rodlike nanoparticles,the rodlike nanoparticles have been first used as the new solid-phase particles of three-phase foam flooding technology in the field of domestic oil development.Based on a large number of laboratory experiments,the rodlike nano Zinc Oxide has been selected as the best solid particle for stabilizing three-phase foams,and the rodlike nano Zinc Oxide-dodecyl dimethyl betaine has been selected as the best three-phase foaming agent for three-phase foam flooding.The experimental results show that the rodlike nano Zinc Oxide-dodecyl dimethyl betaine three-phase foaming agent has the advantages of salt resistance,temperature resistance,acid resistance and alkali resistance.With the new three-phase foaming agent,the maximum recovery ratio and the development effect are the best in the three-phase foam flooding stage after binary combination flooding.In this paper,the mathematical model ofthree-phase foam flooding after binary combination flooding has been established,and the numerical simulation research has been carried out.Based on the sensitivity analysis of the injection parameters of the model,the distribution characteristics of polymer,surfactant,foam,injection-production pressure difference and oil saturation have been studied by numerical simulation,and the seepage law has been thus obtained.In the binary combination flooding stage,the residual polymer in the formation can be used as a foam stabilizer for three-phase foam to further enhance the stability of three-phase foam,so it can have better development effect in the three-phase foam flooding stage without adding other foam stabilizing agent material.Therefore,the three-phase foam flooding after binary combination flooding can improve the oil displacement effect and reduce the development cost.The reduction of interfacial energy is the main driving force for self-assembly of rodlike nanoparticles at the bubble gas-liquid interface.Both the residual surfactant in the binary combination flooding stage and the foaming agent(itself is also a kind of surfactant)used in the three-phase foam flooding stage can reduce the interfacial tension and create a low interfacial energy environment.So it is more conducive to self assembly of rodlike nanoparticles at the foam interface,forming a stable foam coating structure similar to the basket or honeycomb.Therefore,the stability of the three-phase foam can be greatly improved,and the half-life of the foam can be prolonged.The assembly of rodlike nanoparticles at the foam interface is spontaneous,so the foam can be spontaneously stabilized without additional additional conditions.This makes the requirements for the construction environment and construction conditions greatly reduced,so it has the advantages of flexibility and adaptability.At present,there are relatively few researches on three-phase foam flooding after binary combination flooding at home and abroad.The lack of research on its mechanism and influencing factors has greatly restricted the popularization and application of this technology.Therefore,the study of three-phase foam flooding after binary combination flooding can further improve the understanding of the related mechanism and provide theoretical and experimental basis for further popularization and application of the technology.