Insight into the Effect of Natural Fracture Density in a Shale Reservoir on Hydraulic Fracture Propagation: Physical Model Testing

Here, laboratory tests were conducted to examine the effects of natural fracture density (NFD) on propagation hydraulic (HF), HF and (NF) interaction, formation stimulated reservoir volume (SRV). Laboratory methods proposed prepare samples with dense, medium spare discrete orthogonal networks. After conducting a true triaxial fracturing experiment synthetic blocks, experimental results analyzed by qualitative failure morphology descriptions, quantitative analysis used two new indices. On pump pressure profiles, it reflected non-linear interactions between HFs NFs well. For rock blocks dense DFN density, curves present fluctuation shape degree interaction NF is strong; however, for model sparse sudden drop shape. In addition, different behaviors NFs—offset, divert, branch, cross NF—can be observed from fractured blocks. By using index “P-SRV”, relationship NFD effectiveness was further confirmed. Furthermore, most striking finding that mixed mode I–II I–III types can formed in naturally The are beneficial grasping influential mechanism developing more accurate full 3D-coupled simulation models unconventional oil gas development.