The generation of a fracture network in reservoir rocks for fluids to flow via hydraulic fracturing is important in shale oil and gas development, and the intersection between hydraulic and natural fractures is key in bridging natural fractures. In this work, the intersection behaviors between hydraulic and natural fractures and fracture propagation in a three-dimensional (3D) space were investigated. A hydraulic fracturing lab facility is designed and a series of fracturing tests on eight underground cores from the Kong shale reservoir are carried out. First, visualization analysis was conducted on each sample before and after fracturing with the assistance of an X-ray CT scan and the following up 3D reconstruction. Second, an extension model of fracture intersection between natural and hydraulic fractures is established in 3D through analytical calculations. Finally, the intersection behaviors are classified into six zones according to our model analysis. Apart from interesting results and findings, insights into the formation and propagation of fracture networks are also provided, which are of great value in characterizing shale reservoirs.

水力压裂在储层岩石中形成裂缝网络，流体通过水力压裂流动在页岩油气开发中具有重要意义，而水力裂缝与天然裂缝的交汇是桥接天然裂缝的关键。在这项工作中，研究了水力裂缝和天然裂缝之间的交叉行为以及三维 (3D) 空间中的裂缝扩展。设计了一个水力压裂实验室设施，并对孔页岩储层的八个地下岩心进行了一系列压裂试验。首先，在 X 射线 CT 扫描和后续 3D 重建的帮助下，对每个样品在压裂前后进行可视化分析。第二，通过解析计算建立了天然裂缝和水力裂缝之间裂缝交叉的扩展模型3D。最后，根据我们的模型分析，交叉路口行为被分为六个区域。除了有趣的结果和发现之外，还提供了对裂缝网络的形成和扩展的见解，这在表征页岩储层方面具有重要价值。