A theoretical model for 3D hydraulic fracture intersecting with natural fracture

Hydraulic fracturing has been widely applied to enhance the productivity of shale gas reservoir. Natural fractures and weak layers usually exist in the reservoir formation. There are generally three modes when a hydraulic fracture reaches natural fracture, namely crossing, opening and slippage. The complex fracture network can improve the efficiency of extraction. Several of 2D models have been developed to describe the behavior of hydraulic fracture intersecting with natural fracture, which usually ignore the effects of vertical stress and dip angle. To accurately predict the intersecting mode, a 3D fracture intersection model is proposed considering the critical fluid pressures. Predictions of the developed model show good agreement compared with the experi-mental data. It is noted that the distribution of intersecting modes depends on the in-situ stress, the properties of the formation, the coefficient of friction, the cohesion of natural fracture, the strike and dip angle of natural fracture. Sensitivity of the parameters in the developed model is investigated, which affects the redistribution of crossing, opening and slippage zone.