Modelling the Bohemian Earthquake Swarms: Application of a poro-thermo-elastic plastic model with weakening, damage and multiphase flow in GPU

我们建议应用一个新开发的模型来数值研究地震群一般和波希米亚群特别是。该模型模拟了孔隙弹性塑性流变学与压力传播的非线性扩散模型相结合，其中非线性是通过渗透率的有效应力依赖性产生的。目前正在实施一个两相（水和气体）流动模型。在模型中的数值裂纹成核和增长的响应：i）远场应力开发的边界，ii）应力扰动所产生的内部裂纹的增长，和iii）孔隙弹性应力。最近的发展，包括硬化，软化，和损伤增长模型再现整个（加载-故障-卸载）的应力-应变曲线在实验室岩石实验中观察到的。在这个项目中，我们建议：1）包括一个热流模型，并引入热弹性; 2）将模型扩展到3维，3）在图形处理器（GPU）平台上实现模型，4）将模型应用于波希米亚群。与标准CPU架构相比，GPU平台允许快速和非常高分辨率的模拟。数值模型非常适合研究波希米亚群，因为波希米亚地震群的主要物理模拟，即复杂的相互作用和反馈的CO2注入，地震滑移（伴随渗透率提高）流体流动，和对流热流。该模型将被用来解决：a）触发机制，产生震群地震活动，B）故障相关的流体运输过程和迁移过程中的流体/岩石相互作用的影响，和c）调查系统的压力和温度的依赖。

We propose to apply a newly developed model to numerically investigate earthquake swarms in general and the Bohemian swarms in particular. The model simulates a pore-elastic plastic rheology coupled with a non-linear diffusion model for pressure propagation, where the nonlinearity arises through the effective stress-dependence of the permeability. A two-phase (water and gas) flow model is currently being implemented. Numerical cracks in the model nucleate and grow in response to; i) far-field stresses developed at the boundaries, ii) stress perturbations arising from internal crack growth, and iii) poro-elastic stressing. Recent developments that include hardening, softening, and a damage growth model reproduce the entire (load-failure-unload) stress-strain curve observed in laboratory rock experiments. In this project, we propose to: 1) Include a heat flow model and introduce thermo-elasticity; 2) extend the model to 3-dimensions, 3) implement the model on the Graphics Processing Unit (GPU) platform, and 4) apply the model to the Bohemian swarms. The GPU platform allows fast and very high-resolution simulations in comparison to the standard CPU architecture. The numerical model is ideally suited to study the Bohemian swarms because the dominant physics of the Bohemian earthquake swarms are simulated, namely the complex interactions and feedbacks of CO2 injection, seismic slip (with the concomitant permeability enhancement) fluid flow, and advective heat flow. The model will be used to address: a) triggering mechanisms that generate swarm-earthquake activity, b) characterize fault-related fluid transport processes and effects of the fluid/rock interaction during migration, and c) investigate the system’s dependence on pressure and temperature.