In discrete fracture network (DFN) modeling, fractures are randomly generated and placed in the model domain. The rock matrix is considered impermeable. Small fractures and isolated fractures are often ignored to reduce computational expense. As a result, the rock matrix between fractures could be large and intersections may not be found between a well introduced in the model and the hydraulically connected fracture networks (fracture backbones). To overcome this issue, this study developed a method to conceptualize a well in a three‐dimensional (3D) DFN using two orthogonal rectangular fractures oriented along the well's axis. Six parameters were introduced to parameterize the well screen and skin zone, and to control the connectivity between the well and the fracture backbones. The two orthogonal fractures were discretized using a high‐resolution mesh to improve the quality of flow and transport simulations around and along the well. The method was successfully implemented within dfnWorks 2.0 (Hyman et al. 2015) to incorporate a well in a 3D DFN and to track particles leaving an injection well and migrating to a pumping well. Verification of the method against MODFLOW/MODPATH found a perfect match in simulated hydraulic head and particle tracking. Using three examples, the study showed that the method ensured the connectivity between wells and fracture backbones, and honored the physical processes of flow and transport along and around wells in DFNs. Recommendations are given for estimating the values of the six introduced well parameters in a real‐world case study.

中文翻译：

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三维离散断裂网络模型中油井的一种表示方法

在离散裂缝网络（DFN）建模中，随机生成裂缝并将其放置在模型域中。岩石基质被认为是不可渗透的。通常会忽略小裂缝和孤立裂缝，以减少计算费用。结果，裂缝之间的岩石基质可能很大，并且在模型中引入的油井与水力连接的裂缝网络（裂缝主干）之间可能找不到交集。为了克服这个问题，本研究开发了一种方法，该方法使用两个沿井眼轴定向的正交矩形裂缝在三维（3D）DFN中概念化井眼。引入了六个参数来对井眼筛网和表层区域进行参数化，并控制井眼与裂缝主干之间的连通性。使用高分辨率网格将两个正交裂缝离散化，以提高井周围和沿井的流动和传输模拟的质量。该方法已在dfnWorks 2.0中成功实施（Hyman等人，2015年），将一个井合并到3D DFN中并跟踪离开注入井并迁移到泵井的颗粒。针对MODFLOW / MODPATH的方法进行了验证，发现在模拟的液压头和颗粒跟踪中可以完美匹配。通过三个示例，研究表明，该方法确保了井与裂缝主干之间的连通性，并尊重了DFN中沿井及其周围井的流动和运输的物理过程。在实际案例研究中，提出了一些建议，以估算六个引入的井参数的值。