Numerical simulation of in-fracture plugging behavior of temporary plugging agents in diverting fracturing of deep shale gas reservoirs

In-fracture diverting fracturing is an effective technique for improving the quality of fracture network construction in deep shale gas reservoirs. However, theoretical guidance for the injection of temporary plugging agents (TPAs) remains limited. To investigate the transport and plugging behavior of TPAs within fractures under different injection parameters, a wedge-shaped fracture model considering proppant dune distribution is established, and a CFD–DEM coupling method is employed to perform numerical simulations. The results indicate that gravity and fluid drag play dominant roles in TPA transport within fractures. At the initial stage, particles settle under gravity. With increasing particle accumulation, restricted flow space enhances drag and drives particles toward the fracture end. In narrow fracture sections, particle interactions intensify. Large particles preferentially form bridges, and smaller particles fill the voids, resulting in a stable temporary plugging layer. An appropriate particle size proportion, moderate TPA concentration, increased injection velocity, and low-viscosity fracturing fluid are favorable for achieving efficient in-fracture temporary plugging. These findings provide theoretical support for optimizing TPA injection parameters in in-fracture diverting fracturing of deep shale gas reservoirs.