压裂充填防砂完井要求裂缝保持较高的无因次导流能力,支撑剂在裂缝中的运移和铺置对导流能力有直接影响.为了分析支撑剂在疏松砂岩压裂裂缝中的运移规律,利用欧拉方法描述压裂液流体和支撑剂颗粒在压裂充填过程中的运动,建立了数值模拟模型.通过模拟计算得出了压裂液排量和黏度对裂缝内支撑剂运移的影响规律.计算结果表明,压裂液排量越高,支撑剂运移距离越远,悬浮量越多,形成砂堤的速度越快.当压裂液黏度为300 mPa·s,排量大于2.3m3/min时,支撑剂在裂缝中均匀分布,几乎不发生沉降.同时,压裂液黏度增加,支撑剂运移距离和悬浮量均增加.当压裂液排量为1.4m3/min,表观黏度超过200mPa·s时,大部分支撑剂在运移过程中能够被悬浮到裂缝中.模拟计算结果对压裂充填完井压裂液黏度选择和排量设计具有指导意义.
Fracturing and filling sand control completion requires high dimensionless conductivity of fractures.Proppant migration and placement in fractures have a direct impact on the conductivity.In order to analyze the migration of proppant in unconsolidated sandstone fracturing fractures,a numerical simulation model was established to describe the movement of fracturing fluid and proppant particles during fracturing and filling by Euler method.The effects of fracturing fluid displacement and viscosity on proppant migration in fractures were obtained through simulation calculation.The calculation results show that when the fracturing fluid displacement increases,the proppant migration distance becomes faster,the more suspended amount increases,and formation of sand bank becomes faster.When the fracturing fluid viscosity is 300 mPa·s and the flow rate is greater than 2.3 m3/min,the proppant is evenly distributed in the fracture and almost no settlement occurs.At the viscosity of fracturing fluid increases,the migration distance and suspension amount of proppant would increase.When the fracturing fluid displacement is 1.4 m3/min and the apparent viscosity exceeds 200 mPa·s,most of the proppant can be suspended into the fracture during migration.The simulation results are of guiding significance to the viscosity selection and displacement design of fracturing fluid in fracturing and filling completion.