Various fracture patterns may develop through hydraulic fracture propagation and interaction with natural fractures which may substantially enhance connectivity and connected fracture surface area in low-permeability formations. Key factors controlling this behavior are analyzed using the continuum simulator TOUGHREACT-FLAC3D that couples the evolution of stress and deformation (FLAC3D) with reactive fluid flow (TOUGHREACT) in fractured rock. The three potential interaction scenarios are accommodated - for the hydraulic fracture to directly cross, stay arrested by, or reinitiate from the intersected natural fracture. The results show that the combined effects of approach-angle and differential stress affect the normal closure response acting on fractures. Also, larger approach-angles, greater stress differences, and higher fracture shear strength favor direct crossing, with tensile stresses more readily transferred to the far-side of the approached natural fracture. Higher injection rates accelerate buildup of wellbore and fracture pressures which lead to more rapid propagation of the hydraulic fracture. Higher injection rates also increase the wellbore pressure and pressure gradient when injection rate exceeds leak-off rate of fractures arrested by the natural fracture. The presence of only single natural fractures results in faster hydraulic fracture propagation and greater propagation length driven by higher developed wellbore pressures than where dual natural fractures are present. The presence of dual parallel natural fractures hinders the propagation of the hydraulic fracture along its preferred original path as a result of greater and redistributed leak-off and diminution of pressure through the natural fractures. Increased natural fracture permeability slows hydraulic fracture propagation by increasing fluid flow and resulting pressure dissipation by the natural fractures. Combined, these factors influence mechanisms of fracture propagation and interaction, and evolution of flow paths, which are essential in design of hydraulic fracturing treatments, hydro-mechanical characterization and prediction of the response of stimulated fracture networks.

通过水力裂缝扩展和与天然裂缝的相互作用可能会发展出各种裂缝模式，这可能会大大增强连通性和连通的裂缝表面低渗透地层区域。使用连续介质模拟器 TOUGHREACT-FLAC3D 分析控制这种行为的关键因素，该模拟器将应力和变形的演变 (FLAC3D) 与裂隙岩石中的反应流体流动 (TOUGHREACT) 耦合。考虑了三种潜在的相互作用场景——水力压裂直接穿过相交的天然裂缝、被其阻滞或重新启动。结果表明，接近角和差分应力的综合作用影响作用在裂缝上的正常闭合响应。此外，更大的接近角、更大的应力差和更高的裂缝剪切强度有利于直接交叉，拉应力更容易转移到接近的天然裂缝的远侧。较高的注入速率会加速导致水力压裂更快速扩展的井眼和压裂压力。更高的注入率也会增加井眼压力和压力梯度当注入速率超过被天然裂缝阻断的裂缝的漏失速率时。与存在双天然裂缝的地方相比，仅存在单一天然裂缝导致更快的水力裂缝扩展和更大的扩展长度，由更高的开发井眼压力驱动。双平行天然裂缝的存在阻碍了水力压裂沿着其首选原始路径的扩展，这是由于通过天然裂缝的更大和重新分布的泄漏和压力减小的结果。增加的天然裂缝渗透率通过增加流体流量和由天然裂缝引起的压力消散而减慢水力裂缝扩展。结合起来，这些因素影响裂缝扩展和相互作用的机制，以及流动路径的演变，处理、流体力学表征和增产裂缝网络响应的预测。