Hydraulic fracture propagation paths modeled using time-stepped linear superposition method (TLSM): Application to fracture treatment stages with interacting hydraulic and natural fractures at the wolfcamp field test site (HFTS)

A new fracture propagation simulator, based on a time-stepped expansion (TLSM) of the 2D linear superposition method (LSM), is applied here to study the growth of hydraulic fractures from the perforations outward. Based on the resultant displacement vector field, TLSM computes the displacement gradient tensor field, and strain tensor field at each time-step. A constitutive equation is used to compute the local stress field and stress concentrations from the strain tensor field solutions. We apply TLSM to a field case comprised of a subset of wells from the Hydraulic Fracture Test Site (Reagan County, Midland Basin). The well spacing and perforation spacing in the fracture treatment stages are used, together with the zipper mode fracture treatment schedule and the typical natural fracture trend, as identified from core data and associated fracture diagnostics. TLSM results provide a more nuanced insight in the possible mode of fracture propagation and observed diffuse response in micro-seismic clouds monitored during fracture treatment. Our TLSM results suggest that real-world fracture propagation is not necessarily constrained to planar fractures, which may be a geometrical constraint following from the initial assumptions in commonly used commercial fracture simulators.