Hydraulic fracturing is a necessary production enhancement procedure for low permeable conglomerate reservoirs. To study the hydraulic fracture (HF) propagation mechanism in strong heterogeneous conglomerate reservoirs, a numerical simulation based on the modified global cohesive zone method (CZM) was proposed. Two types of geological conglomerate models were built, and natural fractures were also considered in each model. A comprehensive discussion of the treatment parameters for the fracture geometry and width was also conducted. Numerical simulations suggest that a zig-zig fracture can be formed in all cases, while micro fractures emerge near the main fracture, and the number of micro fractures is larger for the composite gravel model than for the single gravel model. The presence of stiff gravel can affect the fracture propagation path and the associated conductivity and can sometimes result in an asymmetric fracture propagation path. The contribution effect of micro fracture on production might be debatable because of the relatively small fracture width. Four different mechanical behaviors, namely, penetration, deflection, attraction and termination, can be observed. In addition, fracture penetration tends to occur near the wellbore zone, while fracture branching generally occurs at the HF tip. The number of fracture deflection modes dominates the fracture behavior regardless of the distance between the HF and the gravel. The in situ stress condition determines the overall fracture propagation path, but the fracture starts to deviate under a low principal stress difference. An increase in the pump rate controls the fracture length due to a sufficiently large fluid injection volume. The increase in fracturing fluid viscosity does not affect the fracture geometry to a large extent but can heavily arrest fracture closure, thus improving fracture width, which can mitigate the large fracture width reduction along the gravel edge. Compared to the homogeneous rock model, the numerical simulation based on the adopted CZM method can be from a more complex fracture type with the conglomerate model, while numerical results can be validated by the triaxial fracturing simulation in the whole and local areas, which demonstrates the ability to perform a numerical simulation of HF propagation in reservoirs with strong heterogeneity.

对于低渗透性砾岩油藏，水力压裂是必不可少的增产步骤。为了研究强非均质砾岩储层中的水力压裂（HF）传播机理，提出了一种基于改进的整体粘性带方法（CZM）的数值模拟。建立了两种类型的地质集团模型，并且在每个模型中还考虑了自然裂缝。还对断裂几何形状和宽度的处理参数进行了全面讨论。数值模拟表明，在所有情况下都可以形成锯齿形裂缝，而在主裂缝附近会出现微裂缝，复合砾石模型的微裂缝数量要大于单砾石模型。坚硬的砾石的存在会影响裂缝的传播路径和相关的电导率，有时会导致裂缝的传播路径不对称。由于裂缝宽度相对较小，因此微裂缝对生产的贡献作用值得商bat。可以观察到四种不同的机械行为，即渗透，挠曲，吸引和终止。另外，裂缝渗透倾向于在井眼区域附近发生，而裂缝分支通常发生在HF尖端处。无论HF与砾石之间的距离如何，裂缝变形模式的数量都决定着裂缝的行为。原位应力条件决定了整体裂缝的传播路径，但裂缝在较低的主应力差下开始发生偏移。由于足够大的流体注入量，泵速的增加控制了裂缝的长度。压裂液粘度的增加不会在很大程度上影响裂缝的几何形状，但会严重阻止裂缝闭合，从而改善裂缝宽度，从而可减轻沿砾石边缘的裂缝宽度的大幅度减小。与均质岩石模型相比，采用CZM方法进行的数值模拟可以采用较复杂的砾岩模型，而数值结果可以通过三轴断裂模拟在整个和局部区域进行验证，这表明了在非均质性强的储层中进行HF传播数值模拟的能力。压裂液粘度的增加不会在很大程度上影响裂缝的几何形状，但会严重阻止裂缝闭合，从而改善裂缝宽度，从而可减轻沿砾石边缘的裂缝宽度的大幅度减小。与均质岩石模型相比，采用CZM方法进行的数值模拟可以采用较复杂的砾岩模型，而数值结果可以通过三轴断裂模拟在整个和局部区域进行验证，这表明了在非均质性强的储层中进行HF传播数值模拟的能力。压裂液粘度的增加不会在很大程度上影响裂缝的几何形状，但会严重阻止裂缝闭合，从而改善裂缝宽度，从而可减轻沿砾石边缘的裂缝宽度的大幅度减小。与均质岩石模型相比，采用CZM方法进行的数值模拟可以采用较复杂的砾岩模型，而数值结果可以通过三轴断裂模拟在整个和局部区域进行验证，这表明了在非均质性强的储层中进行HF传播数值模拟的能力。这样可以减轻沿砾石边缘的大裂缝宽度减小。与均质岩石模型相比，采用CZM方法进行的数值模拟可以采用较复杂的砾岩模型，而数值结果可以通过三轴断裂模拟在整个和局部区域进行验证，这表明了在非均质性强的储层中进行HF传播数值模拟的能力。这样可以减轻沿砾石边缘的大裂缝宽度减小。与均质岩石模型相比，采用CZM方法进行的数值模拟可以采用较复杂的砾岩模型，而数值结果可以通过三轴断裂模拟在整个和局部区域进行验证，这表明了在非均质性强的储层中进行HF传播数值模拟的能力。