悬浮颗粒在孔喉中的微观运移模拟研究

Simulation Study on Microscopic Transport of Suspended Particles in Pore Throats

悬浮颗粒多孔介质微观运移模拟正逐渐成为颗粒堵塞机理研究和地层伤害评价的一种快速而有效的研究方法,基于颗粒离散元方法建立了一种悬浮颗粒在多孔介质中运移的微观孔隙模拟方法。通过拟合宏观力学参数生成了Antler天然砂岩骨架颗粒模型,建立了骨架颗粒流体耦合孔隙网络模拟方法,通过达西线性流验证了骨架颗粒流体耦合模型的正确性。之后在分析悬浮颗粒受力基础上,建立了耦合的悬浮颗粒侵入模型,模型考虑了侵入颗粒与流体、侵入颗粒与骨架颗粒的相互作用。模拟结果表明,在发生贯穿性堵塞时粒径小的悬浮颗粒造成更大地层伤害,初始孔隙度大的岩芯的渗透率降低幅度较大,因此在防止地层伤害注水方案设计时要针对具体地层的孔隙度和渗透率情况严格控制悬浮颗粒的粒径和浓度。

The microscopic transport simulation of suspended particles in porous media is becoming a fast and effective method to study the particle clogging mechanism and to evaluate formation damage. Based on the particle discretization method, a micro-pore simulation method describing the transport of suspended particles in porous media was established. The Antler natural sandstone skeleton particle model was established by fitting the macroscopic mechanical parameters. A simulation method for coupled skeleton particle fluid and pore network was developed. The accuracy of the skeleton particle fluid coupling model was verified by Darcy linear flow. Then, based on the analysis of the force of the suspended particles, the coupled model for the injection of the suspended particles was established considering the interaction between the injected particles and the fluid, injected particles, and skeleton particles. The simulation results show that when complete clogging occurred, the smaller suspended particles cause greater formation damage, and the permeability of the core with large initial porosity decreases greatly.Therefore, during the design of the water injection scheme, the particle size and concentration of suspended particles should be strictly controlled based on the porosity and permeability of the specific formation.