Effect of fluid pressure heterogeneity on injection-induced fracture activation
Effect of fluid pressure heterogeneity on injection-induced fracture activation
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DOI：
10.1016/j.compgeo.2020.103589
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发表时间：
2020-07
影响因子：
5.3
通讯作者：
Yinlin Ji;W. Wanniarachchi;Wei Wu
中科院分区：
文献类型：
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作者：
Yinlin Ji;W. Wanniarachchi;Wei Wu
本研究旨在了解岩石裂缝中流体压力非均匀性的发展及其对裂缝注入诱导激活的影响。我们首先进行注射驱动剪切试验锯切裂缝接近临界应力状态，使用三轴剪切流设置。在流体注入期间测量注入和监测压力，直到裂缝被激活。然后，我们使用COMSOL multiphysics软件恢复裂缝上的流体压力分布的实验数据的基础上。当流体压力不均匀程度较低时，裂缝上流体压力的增加几乎是均匀的，用莫尔-库仑破裂准则可以很好地预测裂缝破裂时的流体压力。然而，当流体压力高度不均匀时，裂缝破裂可以在高压流体区域诱发，并且扩展以激活整个裂缝。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增加而增加。
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.