Numerical modeling of near-wellbore diverter bridging in hydraulic fracturing

Abstract

In this work, we used a particle transport model integrated into the fluid solver in FLAC to simulate the transport of particles in the near-wellbore region inside a hydraulic fracture. Complex flow behaviors, including divergent flow near the fracture entrance and detouring flow around diverter packs, can be captured in this coupling system. In the numerical implementation, the coupled fluid flow and particle transport are realized by updating the fracture permeability, particle concentration, and velocities of fluid and particles in each time step. Simulation results indicate that the final shape of the particle bridging zone at the near-wellbore region is determined by the flow-driven and settling-driven particle transport. A continuous bridging band initially forms at the bottom region of the fracture, then the fluid-driven particles move upwards to block the top region of the fracture. Lastly, a V-shaped bridging band is formed inside the fracture. It is observed that high initial particle concentration and large particle size result in the creation of a small-scale bridging band near the injection entrance, which promotes the rapid growth of the closed bridging band and high-pressure buildup.