Robustness to formation geological heterogeneities of the limited entry technique for multi-stage fracturing of horizontal wells

Excerpt

All horizontal wells in unconventional reservoirs are stimulated today by hydraulic fracturing in a sequential manner from the “toe” to the “heel” of the well (“multi-stage fracturing”). Typically, a fracturing stage consists in performing a hydraulic fracturing treatment over a section of the well isolated by a bridge plug from the previously created hydraulic fractures. One stage contains N perforation “clusters”, typically between two and six, spaced from 10 to 30 m apart. A perforation cluster is the point of initiation of a hydraulic fracture. The technology therefore relies on the initiation and propagation of N hydraulic fractures simultaneously, balancing gain in rig time (large N) and robustness of the process (small N). In this note, using a recently developed numerical model (Lecampion and Desroches 2015), we investigate the effects of in-situ heterogeneities on the initiation and propagation of simultaneous hydraulic fractures and how well these effects can be mitigated. …