Evaluation of Oil Displacement Performance of Imbibition Oil Displacement Agent in an Oilfield

According to the characteristics of Low and extra-low permeability reservoirs in an oilfield, the crude oil in the oilfield was used as the experimental oil, and the deionized water was used as the experimental simulated water. The oil displacement performance of VES (viscoelastic) surfactant oil displacement agent and nano-sized oil displacement agent was evaluated by indoor core simulation oil displacement experiment. The results show that the two oil displacement agents have good oil displacement under low permeability conditions, and the recovery rate is higher than 8.97%. At the same concentration, in the agent displacement stage, the VES oil displacement agent has better oil displacement effect. The reason is that the ultra-low interfacial tension of betaine and the solubilization of micelles to oil can improve the oil displacement efficiency to a certain extent. In the imbibition stage, the nano-sized oil displacement agent has better oil displacement effect. The reason is that the nanoparticles optimize the viscoelasticity of betaine, further reduce the oil-water interfacial tension, enhance the deformation ability of oil droplets, and make the capillary imbibition and oil discharge stronger. Considering various factors, VES surfactant oil displacement agent has better oil displacement effect in the displacement stage, while nano-sized oil displacement agent has better oil displacement effect in the imbibition stage. The research in this paper provides technical support for the optimization of imbibition oil displacement agent in the development of Low and extra-low permeability reservoirs.