Ramesh Kumar Kishan, Makhmutov Artur, Spiers Christopher J, Hajibeygi Hadi
Faculty of Civil Engineering and GeoSciences, Delft University of Technology, Delft, 2628, CD, The Netherlands.
Faculty of Geosciences, Utrecht University, Utrecht, 3584, CS, The Netherlands.
Sci Rep. 2021 Oct 4;11(1):19640. doi: 10.1038/s41598-021-99161-8.
A promising option for storing large-scale quantities of green gases (e.g., hydrogen) is in subsurface rock salt caverns. The mechanical performance of salt caverns utilized for long-term subsurface energy storage plays a significant role in long-term stability and serviceability. However, rock salt undergoes non-linear creep deformation due to long-term loading caused by subsurface storage. Salt caverns have complex geometries and the geological domain surrounding salt caverns has a vast amount of material heterogeneity. To safely store gases in caverns, a thorough analysis of the geological domain becomes crucial. To date, few studies have attempted to analyze the influence of geometrical and material heterogeneity on the state of stress in salt caverns subjected to long-term loading. In this work, we present a rigorous and systematic modeling study to quantify the impact of heterogeneity on the deformation of salt caverns and quantify the state of stress around the caverns. A 2D finite element simulator was developed to consistently account for the non-linear creep deformation and also to model tertiary creep. The computational scheme was benchmarked with the already existing experimental study. The impact of cyclic loading on the cavern was studied considering maximum and minimum pressure that depends on lithostatic pressure. The influence of geometric heterogeneity such as irregularly-shaped caverns and material heterogeneity, which involves different elastic and creep properties of the different materials in the geological domain, is rigorously studied and quantified. Moreover, multi-cavern simulations are conducted to investigate the influence of a cavern on the adjacent caverns. An elaborate sensitivity analysis of parameters involved with creep and damage constitutive laws is performed to understand the influence of creep and damage 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 .
用于储存大量绿色气体（如氢气）的一个有前景的选择是地下岩盐洞穴。用于长期地下储能的盐穴的力学性能对长期稳定性和适用性起着重要作用。然而，由于地下储存引起的长期加载，岩盐会发生非线性蠕变变形。盐穴具有复杂的几何形状，并且盐穴周围的地质区域存在大量的材料非均质性。为了在洞穴中安全地储存气体，对地质区域进行全面分析变得至关重要。迄今为止，很少有研究试图分析几何和材料非均质性对长期加载下盐穴应力状态的影响。在这项工作中，我们进行了一项严谨且系统的建模研究，以量化非均质性对盐穴变形的影响，并量化洞穴周围的应力状态。开发了一个二维有限元模拟器，以始终如一地考虑非线性蠕变变形并对第三阶段蠕变进行建模。该计算方案以现有的实验研究为基准进行了验证。考虑到取决于岩石静压力的最大和最小压力，研究了循环加载对洞穴的影响。对几何非均质性（如形状不规则的洞穴）和材料非均质性（涉及地质区域中不同材料的不同弹性和蠕变特性）的影响进行了严格研究和量化。此外，还进行了多洞穴模拟，以研究一个洞穴对相邻洞穴的影响。对与蠕变和损伤本构定律相关的参数进行了详细的敏感性分析，以了解蠕变和损伤对盐穴构型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上公开获取。
