Subsurface formations provide giant capacities for renewable energy storage, when this energy is converted to green fuels such as hydrogen. A promising option for storing large-scale quantities of hydrogen is in subsurface rock salt caverns. Rock salts, however, are known to exhibit nonlinear time-dependent creep deformation. In this work, the complex creep behaviour of rock salt caverns is modelled and simulated through a 2D finite element model using unstructured grids. The developments presented allow for quantification of the state of the stress around the cavern with the aim of aiding assessments of the safety and reliability of the structure in the longer term. The study builds on the principle of minimum potential energy to consistently account for the nonlinear creep deformation using finite elements. Cyclic loading and evolution of damage within the material are incorporated to predict the failure of the material over time. Sensitivity analysis of key parameters is performed to understand the influence of creep on deformation and stress evolution around the salt cavern configurations. The simulator developed in this work is publicly available at https://gitlab.tudelft.nl/ADMIRE_Public/Salt_Cavern.

中文翻译：

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盐穴循环储能：储层尺度岩盐蠕变的非线性有限元建模

地下地层为可再生能源储存提供了巨大的能力，当这种能量被转化为绿色燃料（如氢）时。储存大量氢气的一个有前景的选择是在地下岩盐洞穴中。然而，已知岩盐表现出非线性时间相关蠕变变形。在这项工作中，岩盐洞穴的复杂蠕变行为通过使用非结构化网格的二维有限元模型进行建模和模拟。所呈现的发展允许量化洞穴周围的应力状态，目的是帮助评估结构的长期安全性和可靠性。该研究建立在最小势能原理的基础上，以使用有限元一致地解释非线性蠕变变形。循环加载和材料内损坏的演变被纳入以预测材料随时间的失效。对关键参数进行敏感性分析，以了解蠕变对盐穴结构周围变形和应力演化的影响。在这项工作中开发的模拟器可在 https://gitlab.tudelft.nl/ADMIRE_Public/Salt_Cavern 公开获得。