Fracture complexity refers to the formation of multiple interacting fractures during hydraulic fracturing rather than a single planar fracture. This complexity often results from interactions between hydraulic fractures and geological features such as natural fractures, faults, and layered rock formations.
When a hydraulic fracture encounters these discontinuities, it may branch, offset, or reorient, creating secondary fractures and fracture networks. In some cases, T-shaped fractures or multiple fracture strands may develop.
Fracture complexity is strongly influenced by in-situ stress conditions, the presence of natural fractures, and rock mechanical properties. When the difference between horizontal stresses is small, fractures are more likely to propagate in multiple directions and activate natural fracture systems.
Field observations from mine-back experiments, core studies, and microseismic monitoring show that fracture networks can form in many reservoirs, especially in unconventional shale formations.
Fracture complexity can increase the stimulated reservoir volume (SRV) and improve hydrocarbon flow, but it also makes fracture behavior more difficult to predict and model.
