Fracture propagation model using multiple planar fracture with mixed mode in naturally fractured reservoir

For hydraulic fracture propagation modeling, in the past, single planar fracture approach denotes fracture propagating only in the direction perpendicular to horizontal well regardless of the existence of natural fracture. Recently, the model implements multiple planar fracture being able to describe the propagation more realistically. For fracture crossing criterion between hydraulic fracture and natural fracture, the hydraulic fracture propagation is generally assumed to be a multiple planar fracture with opening mode. This study proposes a new multi-stage hydraulic fracture propagation model using multiple planar fracture with mixed mode by linearly superposing two modes of opening and sliding. This model is then coupled with commercial reservoir flow simulator through grid mapping process in the form of discrete fracture network developed in this work. The modeling results for the verification about hydraulic fracture crossing natural fracture excellently matched with experimental results for various cases of intersection angle and maximum horizontal stress. In the investigation for inclination angle, frictional coefficient of fracture interface, and fracture orientation, hydraulic fracture passed through natural fracture appropriately corresponding to crossing criterion, and thereafter, propagated in a manner suitably consistent with respect to fracture reinitiation angle. The model of this study is compared to the model with opening mode and also the model of single planar fracture approach. The result shows that there is a large discrepancy in stimulated reservoir volume, because of a number of intersections of fracture connectivity. In the application of the model for Barnett shale reservoir, the stimulated reservoir volume of the model developed in this study and commercial model are calculated differently which indicates that the model of this study is important in evaluating the initial gas in place estimated by stimulated reservoir volume.