Subsurface geological formations provide giant capacities for large-scale (TWh) storage of renewable energy, once this energy (e.g. from solar and wind power plants) is converted to green gases, e.g. hydrogen. The critical aspects of developing this technology to full-scale will involve estimation of storage capacity, safety, and efficiency of a subsurface formation. Geological formations are often highly heterogeneous and, when utilized for cyclic energy storage, entail complex nonlinear rock deformation physics. In this work, we present a novel computational framework to study rock deformation under cyclic loading, in presence of nonlinear time-dependent creep physics. Both classical and relaxation creep methodologies are employed to analyze the variation of the total strain in the specimen over time. Implicit time-integration scheme is employed to preserve numerical stability, due to the nonlinear process. Once the computational framework is consistently defined using finite element method on the fine scale, a multiscale strategy is developed to represent the nonlinear deformation not only at fine but also coarser scales. This is achieved by developing locally computed finite element basis functions at coarse scale. The developed multiscale method also allows for iterative error reduction to any desired level, after being paired with a fine-scale smoother. Numerical test cases are studied to investigate various aspects of the developed computational workflow, from benchmarking with experiments to analysing the impact of nonlinear deformation for a field-scale relevant environment. Results indicate the applicability of the developed multiscale method in order to employ nonlinear physics in their laboratory-based scale of relevance (i.e., fine scale), yet perform field-relevant simulations. The developed simulator is made publicly available at https://gitlab.tudelft.nl/ADMIRE_Public/mechanics.

一旦将这种能量（例如来自太阳能和风力发电厂的能量）转化为绿色气体（例如氢），地下地质构造便为大规模（TWh）存储可再生能源提供了巨大的能力。将该技术全面开发的关键方面将涉及对地下地层的存储容量，安全性和效率的估算。地质构造通常是高度非均质的，并且当用于循环能量存储时，需要复杂的非线性岩石变形物理学。在这项工作中，我们提出了一种新颖的计算框架，以研究存在非线性时变的蠕变物理学的循环载荷下的岩石变形。经典和松弛蠕变方法均用于分析样品中总应变随时间的变化。由于非线性过程，隐式时间积分方案用于保持数值稳定性。一旦在精细尺度上使用有限元方法一致地定义了计算框架，便会开发出一种多尺度策略，不仅可以在精细尺度上而且可以在较粗尺度上表示非线性变形。这可以通过在局部上开发局部计算的有限元基础函数来实现。与细尺度平滑器配对后，开发的多尺度方法还可以将迭代误差减少到任何所需的水平。对数值测试案例进行了研究，以研究已开发的计算工作流程的各个方面，从对基准进行实验到分析非线性变形对现场规模相关环境的影响。结果表明，所开发的多尺度方法的适用性是为了在其基于实验室的相关尺度（即精细尺度）中采用非线性物理学，但仍执行与场相关的模拟。开发的模拟器可在https://gitlab.tudelft.nl/ADMIRE_Public/mechanics上公开获得。