Abstract This study aims to understand the development of fluid pressure heterogeneity in a rock fracture and its influence on the injection-induced activation of the fracture. We first conduct injection-driven shear tests on a sawcut fracture close to a critical stress state using a triaxial shear-flow setup. The injection and monitoring pressures during the fluid injection are measured until the fracture is activated. We then use COMSOL multiphysics software to recover the fluid pressure distribution on the fracture based on the experimental data. When the degree of fluid pressure heterogeneity is low, the increase in fluid pressure on the fracture is nearly uniform, and the fluid pressure at fracture failure can be well predicted by the Mohr-Coulomb failure criterion. However, when the fluid pressure is highly heterogeneous, fracture rupture can be induced in the area with highly pressurized fluid, and propagates to activate the entire fracture. The fluid pressure at fracture failure is much higher than the predicted pressure, and increases with higher degree of fluid pressure heterogeneity.

中文翻译：

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流体压力非均质性对注入诱导裂缝活化的影响

摘要 本研究旨在了解岩石裂缝中流体压力非均质性的发展及其对注入致裂缝活化的影响。我们首先使用三轴剪切流设置对接近临界应力状态的锯切裂缝进行注入驱动剪切测试。测量流体注入期间的注入和监测压力，直到裂缝被激活。然后，我们使用 COMSOL multiphysics 软件根据实验数据恢复裂缝上的流体压力分布。当流体压力非均质性程度较低时，裂缝上流体压力的增加几乎是均匀的，裂缝破坏时的流体压力可以通过Mohr-Coulomb破坏准则很好地预测。然而，当流体压力高度不均匀时，高压流体可诱发裂缝破裂，并扩展激活整个裂缝。裂缝破坏时的流体压力远高于预测压力，并且随着流体压力非均质性程度的提高而增加。