Mechanisms of hydraulic fracturing induced seismicity

大规模的水力压裂已经变得无处不在，使人们能够经济地开采北美巨大的致密油气储量。微震活动通常伴随着水力裂缝的发育，是模拟储集层岩石体积中原有裂缝和断层发生动态滑动的一种表现。这种滑动可能会导致剪切裂缝的扩张，并相应地增加渗透率和储集岩与水力裂缝(HF)的连通性，从而改善最终的产量。在极少数情况下，水力压裂引起的动态滑动会发展成中小型地震。这在一些国家禁止压裂的决定中发挥了作用。因此，重要的是研究由传播的高频引起的应力和孔压扰动引起的动态和准静态断层滑动的机制，以便能够更好地了解a)它如何影响储集层性质和“受刺激的岩石体积”；b)从地震到动态滑动的转变，以及动态破裂失控(地震)的可能性。

Hydraulic fracturing on a massive scale has become ubiquitous in allowing to economically tap vast tight oil and gas reserves in North America. Microseismicity, which usually accompanies growth of hydraulic fractures, is a manifestation of dynamic slippage on pre-existing fractures and faults in the stimulated reservoir rock volume. This slip may lead to dilation of sheared fractures, and associated increase of permeability and connectivity of the reservoir rock to the hydraulic fracture (HF), and, therefore, improvement to eventual production. On rare occasions, dynamic slip induced by hydraulic fracturing is known to grow out into a small-to-moderate size earthquake. This has played a role in some countries' decision to ban fracturing. It is therefore important to study mechanisms of both dynamic and quasi-static fault slip due to stress and pore pressure perturbations introduced by a propagating HF to be able to better understand a) how it impacts reservoir properties and "stimulated rock volume"; b) the transition from aseismic to dynamic slip, and potential for dynamic rupture run-away (an earthquake).