A novel analytical simulation method of utilization of surfactant-active nanoparticles for well injection enhancement in low-permeability reservoirs

Abstract

In order to study the mechanism of surfactant-active nanoparticles in drag reduction and injection enhancement in low-permeability reservoirs and to simulate the rough condition of the pore surface of the reservoirs, we construct a microtube model with periodic rectangular groove structure and a force balance model of nanoparticles on rough surface to get the limit adhesion concentration fraction model of surfactant-active nanoparticles on pore surface. The method of characteristics (MOC) is used to analyze and simulate the seepage process of the suspension-adhesion-plugging coupling of surfactant-active nanoparticles in pores of low permeability reservoirs. By comprehensively considering reservoir damage caused by the mechanisms such as particle attachment and blockage and the slip effect established by nanoparticle attachment, a theoretical model for resistance reduction and injection enhancement of surfactant-active nanoparticles has been formed. The results show that comparing with the core without nanoparticles flooding, the pressure drop of the core decreases significantly after the injection of nanoparticles, and the pressure drop reaches 40%. At the same time, by comparing the water injection index before and after injection, the core injection capacity is significantly improved after the surfactant-active nanofluid injection. This model provides a certain theoretical basis for the technology of pressure reduction and injection enhancement of surfactant-active nanoparticles in low permeability reservoirs.