Starting Conditions of Particle Migration in Tight Sandstone Reservoir Development

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.