Abstract One of the main purposes of hydraulic fracturing in unconventional resources such as shale is to improve the connectivity between existing natural fractures and the production well. Since the inherent permeability of shale is extremely low, this newly formed fracture connectivity provides faster paths for the hydrocarbon stored in preexisting natural fractures. We performed numerical simulations of the free gas production at large scale fractured reservoir with different pre-existing natural fracture network intensities and with variable hydraulic fracture sizes and staging. We explored production characteristics as a function of the properties of both, natural fractures (intensity) and hydraulic fractures (size and staging). Our hypothesis is that once maximum fracture connectivity is achieved, additional stimulation does not increase production significantly. In this numerical study we use an advanced modeling tool to study fractures connectivity, Discrete Fracture Network (DFN) approach, which can represent fracture networks similar to those observed on individual reservoir sites. In our model the horizontal production well and vertical hydraulic fractures were deterministically defined and surrounded by stochastically generated natural fracture networks. The performed numerical experiments show how fracture connectivity depends on hydraulic fracture settings in fractured reservoir with different preexisting fracture densities. We numerically showed that cumulative free gas production is not affected significantly by hydraulic fractures size (25 m–150 m) or spacing (15 m–45 m) for dense natural fracture networks. However, the hydraulic fracture size is important in reservoirs with sparse natural fractures, although spacing (number of stages) does not play a significant role.

中文翻译：

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水力和自然裂缝相互作用对生产的作用

摘要 页岩等非常规资源水力压裂的主要目的之一是提高现有天然裂缝与生产井的连通性。由于页岩的固有渗透率极低，这种新形成的裂缝连通性为储存在预先存在的天然裂缝中的碳氢化合物提供了更快的路径。我们对具有不同预先存在的天然裂缝网络强度和可变水力裂缝尺寸和阶段的大型裂缝性油藏的游离气生产进行了数值模拟。我们探索了作为天然裂缝（强度）和水力裂缝（大小和分段）特性的函数的生产特征。我们的假设是，一旦达到最大裂缝连通性，额外的刺激不会显着增加产量。在这项数值研究中，我们使用先进的建模工具来研究裂缝连通性，即离散裂缝网络 (DFN) 方法，该方法可以表示与在单个储层现场观察到的裂缝网络类似的裂缝网络。在我们的模型中，水平生产井和垂直水力裂缝被确定性地定义并被随机生成的天然裂缝网络包围。进行的数值实验表明，裂缝连通性如何取决于具有不同预先存在裂缝密度的裂缝储层中的水力裂缝设置。我们从数值上表明，对于致密的天然裂缝网络，累积游离气产量不受水力裂缝尺寸（25 m–150 m）或间距（15 m–45 m）的显着影响。然而，