深部煤层气转向压裂缝内暂堵剂运移封堵数值模拟OA

During the development of coalbed methane(CBM),due to the high plasticity of deep coal rock and large in-situ stress difference,temporary plugging and diversion fracturing technique is mainly used to promote com-plex fracture network propagation.However,field fracturing data shows that temporary plugging parameters in some fracturing stages are unreasonable,failing to achieve successful bridging and plugging of the agents within the frac-tures,resulting in diversion failure and consequently impacting the fracturing effect.Considering the influence of proppant sand bank on the migration of temporary plugging agents within fractures,a numerical model for tempo-rary-plugging-agent particle migration and plugging in coal-rock hydraulic fractures is established based on the cou-pling of Computational Fluid Dynamics(CFD)and Discrete Element Method(DEM),exploring the bridging be-havior of temporary plugging agent particles and plugging efficiency under different operational parameters.The re-sults indicate that,when temporary plugging agent is injected,the optimal volume ratio of large-to-small particle size is 4:1.Key factors such as fracturing fluid viscosity,temporary plugging agent volume fraction and fluid injec-tion rate affect the bridging time,plugging volume and bridging distance.The inlet fracture width shows no signifi-cant correlation with the volume of temporary plugging agent,achieving effective temporary plugging at various frac-ture widths.The research provides theoretical guidance for the field temporary plugging and diversion technique in deep coalbed methane and the regulation mechanism of artificial fracture networks.