Study on Flow Diversion Caused by Deformable Preformed Particle Gel

Abstract

Abstract Water channeling becomes severer after long time of water flooding especially in heterogeneous oil reservoirs. Field applications of deformable preformed particle gel (PPG) in China has proved that injection of PPG can lead to flow diversion, increase sweeping efficiency and thus increase oil recovery. However, it is unclear how PPG promotes flow diversion and its controlling influence factors. To address this problem, the paper carries out the microscopic simulation study. The flow of deformable PPG is complex, involving particle deformation, migration, fluid flow and particle-fluid interaction. In the study, the discrete boundary idea of immersed boundary method is used to deal with particle deformation. The lattice boltzmann method (LBM) and immersed moving boundary method (IMB) are combined to simulate the fluid flow considering the existence of particles. The discrete element method (DEM) is used to simulate particle-particle and particle-wall contact. Combining these techniques, the paper studies how deformable PPG migrates in a two-channel model and promotes flow diversion. The effect of particle diameter and elastic modulus on flow diversion is also discussed. The two-channel model simulation results show that the fractional flow increases and decreases alternately between the two channels. This is mainly because the flow resistance increases and forces more subsequent water turns to another channel due to the particle deformation and wall friction when the PPG migrates in one channel. The influencing factor discussions indicate that in a certain extent the flow diversion capacity of deformable PPG increases as the PPG diameter and elastic modulus increase. However, overlarge PPG diameter and elastic modulus may block the small channel. In this situation, the fractional flow of small channel decreases to 0 and the water channeling becomes much more severer. Therefore, the PPG diameter and elastic modulus should be properly selected in order to obtain flow diversion and reduce water channeling in field applications. The paper focuses on how deformable PPG promotes flow diversion, which provides a microscopic interpretation on enhanced oil recovery mechanism of PPG in heterogeneous reservoirs. The influencing factor analyses also provide valuable references for future applications of deformable PPG in more oilfields.