In-Situ Channelization Model for Hydraulic Fracturing Simulation

Abstract In-Situ Channelization (ISC) phenomenon comprises a segregation of proppant and fiber-laden slurry in a hydraulic fracture during fracture closure. The segregation can lead to the creation of highly conductive open channels in the proppant pack and can significantly alter the fracture conductivity. Simulating ISC in a fracturing simulator can help maximize channeled areas, thus suggesting a higher production. The nature of ISC represents the slurry bridging at static conditions due to wall roughness and heterogeneities in proppant and fiber distribution. We demonstrate the development of the static bridging model, which we refer to as anchoring. The model is based on the physical principles, namely the force balance. The parameters governing the phenomenon include slurry composition, temperature, fracture walls surface roughness and orientation. Pixel-type approach to laboratory testing is introduced, which aids in the simplification of the model description and the implementation. Fracture waviness and roughness were found to affect the channelization, with fracture inclination angle being the most contributing factor. The model was extended to high temperatures, allowing simulations in the whole working ranges. Verification and validation showed fairly good reproduction of experimental data with the model, with tolerance of the anchoring event determination being within 5 ppt of fiber concentration. Simulations of hydraulic fracturing in the fracturing simulator with ISC model enabled revealed that ISC phenomenon has significant effect in treatments with low viscous fluids (e.g., linear gel or slick water). Meanwhile the effect diminishes as the reservoir temperature increases.