论文标题
注射诱导的剧烈岩石中的无性震动
Injection-induced aseismic slip in tight fractured rocks
论文作者
论文摘要
我们研究了在2D离散裂缝网络（DFN）中以随机定向且均匀分布的摩擦骨折的恒定压力注射问题。我们表明，这个问题与Bhattacharya和Viesca（2019）调查的单个平面剪切裂缝中更简单的注射情况具有相似之处；维斯卡（Viesca）（2021），其结果在这里扩展到包含封闭形式的溶液，以作为注射体积Vinj的函数，以供无向力矩。值得注意的是，我们证明，断裂的岩体质量的水电反应是一阶的，受单个无量纲参数t的影响，与有利方向的裂缝相关：t的低值（严重压力的条件）导致由于对弹性压力菌株的弹性应激转移而导致的亚s弹性滑移快速迁移，这是对弹性菌株的弹性转移。因此，在这种情况下，DFN渗透数没有对无性滑移的时空演化的影响。另一方面，在略有加压条件下（t> 1），加压区域后面的滑动斑块滞后，因此渗透数会影响到一阶介质的响应。此外，我们表明，在这两个限制条件下，无性矩量表范围vinj^2，类似于单个平面断裂的情况。但是，比例因素取决于在略有加压条件下的DFN特性，而在严重应力的条件下，它似乎仅与DFN性质有些依赖。
We investigate the problem of fluid injection at constant pressure in a 2D Discrete Fracture Network (DFN) with randomly oriented and uniformly distributed frictionally-stable fractures. We show that this problem shares similarities with the simpler scenario of injection in a single planar shear fracture, investigated by Bhattacharya and Viesca (2019); Viesca (2021) and whose results are here extended to include closed form solutions for aseismic moment as function of injected volume Vinj. Notably, we demonstrate that the hydro-mechanical response of the fractured rock mass is at first order governed by a single dimensionless parameter T associated with favourably oriented fractures: low values of T (critically stressed conditions) lead to fast migration of aseismic slip from injection point due to elastic stress transfer on critically stressed fractures. In this case, therefore, there is no effect of the DFN percolation number on the spatio-temporal evolution of aseismic slip. On the other hand, in marginally pressurized conditions (T > 1), the slipping patch lags behind the pressurized region and hence the percolation number affects to a first order the response of the medium. Furthermore, we show that the aseismic moment scales Vinj^2 in both limiting conditions, similarly to the case of a single planar fracture subjected to the same injection condition. The factor of proportionality, however, depends on the DFN characteristics in marginally pressurized conditions, while it appears to be only mildly dependent on the DFN properties in critically stressed conditions.
