A coupled approach of fluid flow and geomechanics is proposed in this study to quantitatively understand the hydraulic fracturing-induced poroelastic effects that activate pre-existing faults and trigger earthquake swarms near Crooked Lake, Alberta. The 3D poroelastic simulation of the seismogenic fault zone is then conducted to characterize the pressure diffusion and stress perturbation that led to fault activation. Results show that the poroelastic effects on the high-permeable damage zones of a conductive-barrier fault triggered the sequential activation of the seismogenic fault in the basement and Winterburn Formation. In addition, the high-permeable damage zones act as conduits for pore pressure diffusion along the fault, whereas the fault core functions as a barrier to prevent crossing flow. The poroelastic effects in terms of pressure diffusion and stress perturbation in response to fluid injection facilitated the fault slip and hence triggered the M_w 3.6 earthquake in the basement formation 40 days after the fracturing operations. Moreover, the mainshock created negative Coulomb failure stress changes, inhibiting further fault slip in the basement formation. Subsequently, the stimulation of another well facilitated poroelastic effects on the fault damage zone in top Winterburn Formation, reactivating the same fault with an M_w 4.1 earthquake 8 days after the initiation of treatments. It is essential to optimize the injection site selection near the existing faults to reduce risks of the induced earthquakes near Crooked Lake.

中文翻译：

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艾伯塔省弯曲湖附近水力压裂作业的孔隙弹性效应引发的两次Mw 3.6和Mw 4.1地震研究

在这项研究中，提出了一种将流体流动与地质力学耦合的方法，以定量地了解水力压裂引起的孔隙弹性效应，该效应激活了先前存在的断层并触发了艾伯塔省弯曲湖附近的地震群。然后进行了地震断层带的3D孔隙弹性模拟，以表征导致断层活化的压力扩散和应力扰动。结果表明，对导电阻挡层断层的高渗透破坏区的孔隙弹性作用触发了基底和温特本地层中地震成因断层的相继活化。此外，高渗透性破坏带还充当孔隙压力沿断层扩散的管道，而断层芯则起到了防止横流的屏障的作用。_w 3.6压裂作业后40天，地下室地层发生地震。而且，主震产生了负的库仑破坏应力变化，从而抑制了地下室地层中进一步的断层滑动。随后，另一口井的刺激促进了对温特伯恩顶层断层破坏带的孔隙弹性作用，在开始处理8天后，又发生了M _w 4.1地震，重新激活了同一断层。必须优化现有断层附近的注入位置，以减少弯曲湖附近诱发地震的风险。