In the tight sandstone oil production stage, the migration of particles will not only block the oil path and throat, but also block the wellbore and damage the equipment. Based on the theory of non-Newtonian fluid, hydrodynamics, the extended Derjaguin Landau Verwey Overbeek (DLVO) theory and the JKR (the model of Johnson–Kendall–Roberts) contact theory, the mathematical model and quantitative analysis of the critical condition of the particle separation from the surface due to the influence of oil flow in the fracture environment are presented in this paper. A theoretical model with pressure gradient as the core parameter and particle size, crack size and various contact forces as variables is established. By adding the formula of non-Newtonian fluid and taking the consistency coefficient and fluidity index as the contrast relation, the change rule of particle migration under the influence of non-Newtonian fluid is obtained. Effective prevention and control measures for the purpose of effectively preventing particle migration are also put forward. The results show that with the increase in the fluidity index, the pressure gradient decreases obviously; with the increase in the consistency coefficient, the pressure gradient increases obviously; and with the increase in particle size, the pressure gradient first decreases and then increases, thus creating a U-shaped curve. The lowest pressure gradient exists under the fixed condition.

The movement of the gas–liquid interface caused by the movement of the bubble position will have an impact on the starting conditions for particle migration. This article quantifies the influence of moving bubbles on the starting conditions of particle migration in non-Newtonian fluids, and it aims to better understand the influence of bubbles moving in non-Newtonian fluids on particle migration to achieve more effective control. First, the forces and moments acting on the particles are analyzed; then, fluid dynamics, non-Newtonian fluid mechanics, extended DLVO (Derjaguin Landau Verwey Overbeek theory), surface tension, and friction are applied on the combined effects of particle migration. Then, we reasonably predict the influence of gas–liquid interface movement on particle migration in non-Newtonian fluids. The theoretical results show that the movement of the gas–liquid interface in non-Newtonian fluids will increase the separation force acting on the particles, which will lead to particle migration. Second, we carry out the particle migration experiment of moving bubbles in non-Newtonian fluid. Experiments show that when the solid–liquid two-phase flow is originally stable, particle migration occurs after the bubble movement is added. This phenomenon shows that the non-Newtonian fluid with bubble motion has stronger particle migration ability. Although there are some errors, the experimental results basically support the theoretical data.

The extraction of shale oil is a hot issue in today’s society where resources are tight. However, the pores of shale oil are complex. The migration of particles in the pores may lead to blockage of narrow oil passages and may also unclog the oil passages. Therefore, this paper studies the particle migration during shale oil development, and uses simulation to find out the particle migration law in laboratory experiments.