Optimal proppant placement is critical to maintaining productivity from stress-sensitive reservoirs, in which gas conductivity depends on the connectivity of the network of secondary fractures to the wellbore. In a colloquial sense, this research places micro-proppants in induced and natural fractures, shows how they are excluded from reaching far into the reservoir, and describes which sizes of proppants this occurs for. Micromechanical modelling of a hydraulic fracturing fluid, in which the hydrodynamics between the fluid and solid phases are fully resolved, is achieved via the lattice Boltzmann method (LBM) for fluids coupled with the discrete element method (DEM) for particles. It is shown that proppant transport along the primary hydraulic fracture channel is strongly inhibited by leak-off into the secondary fracture system. This leak-off is strongly affected by the migration of particles across the fracture width, which in turn is a function of reservoir and treatment properties. A novel numerical approach is proposed for predicting proppant transport through the secondary fracture system, with far-reaching applications to porous media particulate transport.

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