A criterion for identifying hydraulic fractures crossing natural fractures in 3D space

Based on the analysis of the stress fields near the hydraulic fracture tip and on the natural fracture surface, a criterion for identifying hydraulic fractures crossing natural fractures was proposed. A series of hydraulic fracturing tests were conducted to investigate the influences of natural fractures occurrence and horizontal stress contrast on hydraulic fracture propagation using large scale tri-axial fracturing system. The experiment results showed that the crossing happens in the region with high approaching angle and strike angle, large horizontal stresses and horizontal stress difference coefficient. Horizontal stress contrast has a critical value, only when it is above the critical value, may the hydraulic fracture cross the natural fracture. These experimental results agree with the predictions of this criterion well. It is predicted by this criterion that the hydraulic fracture of a test well in the Longmaxi shale formation, Sichuan Basin, can't cross the natural fracture, which agrees with the micro-seismic monitoring results.