水力压裂诱发裂缝动态失稳滑移的响应规律研究

Study on the Response Mechanism of Dynamic Instability and Slip in Fractures Induced by Hydraulic Fracturing

摘要: 随着全球新型能源需求增长，水力压裂等工业活动诱发的地震事件显著增加。文章采用离散元方法，探究了压裂液注入速率(通过增压速率体现)、地应力(通过有效正应力体现)以及压裂液黏度三个主要压裂参数对裂缝动态失稳滑移的影响。结果表明：1) 提高压裂液增压速率会促进裂缝从稳定蠕滑向黏滑运动转变；2) 增加有效正应力会提高裂缝滑移所需的临界剪应力，从而增强其稳定性；3) 压裂液黏度的变化对裂缝失稳激活的临界条件影响不大，但高黏度液体会限制流体扩散、增强局部孔隙压力而加剧滑移量和不稳定性。该研究为油气资源开发中的诱发地震风险防控提供理论指导。

Abstract: With the global growth in demand for new energy sources, induced seismic events triggered by industrial activities such as hydraulic fracturing have significantly increased. This study employs the discrete element method to investigate the effects of three primary fracturing parameters—fracturing fluid injection rate (represented by the pressurization rate), in-situ stress (represented by effective normal stress), and fracturing fluid viscosity—on the dynamic instability and slip of fractures. Results indicate: 1) Increasing the pressurization rate of fracturing fluid accelerates the transition of fractures from stable creep to viscous slip; 2) Elevating effective normal stress raises the critical shear stress required for fracture slip, thereby enhancing stability; 3) Changes in fracturing fluid viscosity have a limited impact on the critical conditions for fracture instability activation. However, high-viscosity fluids exacerbate slip magnitude and instability by restricting fluid diffusion and increasing local pore pressure. This research provides theoretical guidance for mitigating induced seismicity risks in oil and gas resource development.