A numerical simulation study of fracture reorientation with a degradable fiber-diverting agent

• A new mathematical model is established to model the fiber-assisted crack reorientation according to the tensile failure criterion.
• Factors influencing the diverting radius are intensively analyzed through numerical simulation.
• The simulation results are verified with true tri-axial fracture reorientation tests and field application data.

Degradable fiber can temporarily plug a natural fracture or artificial fracture. It has been successfully applied in the stimulated reservoir volume (SRV) fracturing or re-fracturing of unconventional reservoirs. Based on the classical analytical stress field equation, a new mathematical model is established in this paper to model the crack reorientation path after injecting fiber diversion fluid according to the tensile failure criterion. Factors influencing the diverting radius are intensively analyzed through numerical simulation. The results indicate that the horizontal stress difference, fracturing fluid viscosity, and injection time (fracturing fluid volume) have larger effects on the diverting radius than do the formation permeability (1–50 mD) and bottomhole pressure (90–160 MPa). The simulation results are successfully verified, matching well with the experimental data from the true tri-axial fracture reorientation tests in the laboratory. The model is successfully applied to the heterogeneous carbonate reservoirs in northwest China.