PERFORMANCE EVALUATION OF NANO-IMBIBITION OIL DISPLACEMENT AGENT SUITABLE FOR LOW-PERMEABILITY RESERVOIRS

Low-permeability reservoir has low matrix permeability and small pore throat. Conventional enhanced oil recovery methods are difficult to effectively displace crude oil in low-permeability reservoirs. In this work, a new nano-imbibition oil displacement agent (NIAG) was developed by compounding nanoparticle (NI) and surfactant (APEG). The dispersion stability, interfacial tension and wettability were evaluated. Core imbibition and displacement experiments were carried out to study the imbibition and displacement effect of nano-imbibition oil displacement agent in low-permeability cores. The results show that the average particle size of NIAG is 70 nm. It reduces the oil-water interfacial tension to a certain extent, and the oil-water interfacial tension is 0.026 mN/m. It can change the wettability of rock wall, and the change degree of wetting angle can reach 70%. NIAG has good imbibition recovery effect for low-permeability cores. The spontaneous imbibition recovery rate can reach 21.5% at 60 °C, and the imbibition displacement efficiency can reach 37.5%. This work provides a theoretical basis and technical support for the efficient development of low-permeability reservoirs.