Study on the Laws of Proppant Transport and Conductivity Distribution Characteristics Based on the CFD–DEM Method

Hydraulic fracturing remains a key stimulation technique for the development of low‐permeability oil and gas reservoirs. In such systems, the migration and spatial placement of proppants within multi‐level branched fractures play a decisive role in sustaining fracture conductivity and ensuring long‐term production stability. However, most previous studies have focused on simplified single fracture models, with limited attention given to complex branching geometries and the resulting heterogeneous distribution of fracture conductivity. In this study, a coupled computational fluid dynamics–discrete element method (CFD–DEM) method was applied to investigate the governing mechanisms of proppant transport and conductivity evolution in multi‐level branched fracture networks. Numerical models representing both a single main fracture and multi‐level branched fractures were constructed and validated using laboratory‐scale experimental data to confirm model reliability. On the basis of these models, the effects of proppant concentration, particle size, fluid viscosity, and injection velocity on particle migration, sandbank morphology, and fracture conductivity were systematically analyzed. The results show that increasing fracture roughness inhibits particle deposition and extends the transport distance. Higher fluid viscosity and injection velocity drive the sandbank to migrate toward the distal region of the fracture, reducing the filling efficiency of the main fracture while improving proppant placement in far‐well branch fractures. A staged injection strategy that introduces smaller particles in the early stage and larger particles in the later stage can effectively enlarge the propped area and enhance the uniformity of conductivity distribution. In addition, the proppant concentration is recommended to be controlled at approximately 20%, as further increases may weaken the propping performance in distal fracture segments.