Characterizing a Complex Induced Fracture Network: A Case Study of a Diagnostic Fracture Injection Test in the Heterogeneous Overpressured Montney Formation

This study provides new insights into hydraulic fracture growth during a Diagnostic Fracture Injection Test (DFIT) in the presence of mechanical heterogeneity in the overpressured Montney Formation in British Columbia. A novel continuum non-local poro-elastic-plastic model of a Stimulated Rock Volume (SRV) developed in the context of the Finite Element Method is used for analysis. It is shown that DFITs in the Montney Formation can generate substantial fracture network complexity. We provide insights on potential complex fracturing patterns and distributions at the well spacing scale. Additionally, the SRV tends to span and extend several meters away on each side of the induced fracture plane. We quantify the fracture tortuosity factor which appears to deviate significantly from unity, as in the cubic law. It is further demonstrated that the aperture within the SRV can significantly drop after shut-in before it reverts and begin to heal mechanically. We show that the onset of the aperture self-healing coincides with the time when the pressure during the fall-off period becomes equal to the final effective ISIP.