The fracture propagation in hydraulic fracturing is described as a nonlinear problem dynamic boundary. Due to the limitation of mesh refinement, it is difficult to obtain the real crack propagation path using conventional numerical methods. Meshless methods (MMs) are an effective method to eliminate the dependence on the computational grid in the simulation of fracture propagation. In this paper, a hydraulic fracture propagation model is established based on the element-free Galerkin (EFG) method by introducing jump and branch enrichment functions. Based on the proposed method, three types of fracturing technology are investigated. The results reveal that the stress interference between fractures has an important impact on the propagation path. For the codirectional fracturing simultaneously, fractures propagate in a repel direction. However, the new fracture is attracted and eventually trapped by the adjacent fracture in the sequential fracturing case. For the opposite simultaneous fracturing in multiwells, two fractures with a certain lateral spacing will deflect toward each other. The effect of stress shadow should be used rationally in the optimization of construction parameters; for the single well multistage fracturing, the stage spacing should be out of stress inversion area, while for the simultaneous fracturing of multiple wells, stress inversion zones should be used to maximize communication between natural fractures. Overall, this study establishes a novel and effective approach of using MM to simulate the propagation of hydraulic fractures, which can serve as a useful reference for understanding the mechanism of hydraulic fracture propagation under various conditions.

中文翻译：

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基于无网格法的水力裂缝延伸数值研究

水力压裂中的裂缝扩展被描述为非线性问题动态边界。由于网格细化的限制，使用常规数值方法难以获得真实的裂纹扩展路径。无网格方法（MMs）是一种有效的方法，可以消除裂缝扩展模拟中对计算网格的依赖。在本文中，通过引入跳跃和分支富集函数，基于无单元Galerkin（EFG）方法建立了水力裂缝扩展模型。基于所提出的方法，研究了三种类型的压裂技术。结果表明，裂缝之间的应力干扰对传播路径有重要影响。对于同时同向压裂，裂缝沿排斥方向扩展。然而，在顺序压裂的情况下，新的裂缝被相邻的裂缝吸引并最终被困住。对于多井反向同时压裂，具有一定横向间距的两条裂缝会相互偏斜。施工参数优化中应合理利用应力影效应；对于单井多级压裂，级距应在应力反演区之外，而对于多井同时压裂，应利用应力反演带，最大限度地连通天然裂缝。总体而言，本研究建立了一种新的、有效的利用MM模拟水力压裂扩展的方法，可为理解不同条件下水力压裂扩展机制提供有益的参考。