In domal and bedded rock salt geothermal reservoirs, geochemical dissolution of the in-situ rock salt formation can alter fluid transport properties, thus impacting fluid flow. Coupled Hydro-mechanical–chemical (HMC) modeling is a useful tool to evaluate fluid transport through rock salt geothermal systems and to assess their economic potential. Existing continuum-based numerical simulation of fluid transport through rock salt relies on the polyhedral orientation of rock salt crystal boundaries as potential fluid pathways, employing a deformation-dependent permeability model to depict pressure-driven fluid flow through rock salt. However, this numerical approach is exclusively HM-coupled and overlooks the influence of halite dissolution/precipitation on the permeability model. This study extends the deformation-dependent permeability model to account for halite dissolution by adopting a reverse mineral growth approach. Using this extended (HMC-coupled) model, we capture the relevance of geochemical reactions on the response of rock salt formations undergoing pressure-driven fluid percolation. The resulting simulations predict a lower fluid pressure than the HM-coupled scenario, highlighting the impact of halite dissolution on fluid flow through rock salt.

中文翻译：

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流体通过岩盐渗透的完全耦合水-机械-化学连续体建模


在圆顶岩盐和层状岩盐地热储层中，原位岩盐层的地球化学溶解会改变流体输送特性，从而影响流体流动。耦合水力-机械-化学 （HMC） 建模是评估流体通过岩盐地热系统传输并评估其经济潜力的有用工具。现有的基于连续体的流体通过岩盐传输的数值模拟依赖于岩盐晶体边界的多面体取向作为潜在的流体路径，采用变形依赖性的渗透率模型来描述压力驱动的流体流经岩盐。然而，这种数值方法完全是 HM 耦合的，忽略了岩盐溶解/沉淀对渗透率模型的影响。本研究通过采用逆矿物生长方法扩展了变形依赖性渗透率模型，以解释岩盐的溶解。使用这个扩展的（HMC 耦合的）模型，我们捕捉了地球化学反应对经历压力驱动流体渗流的岩盐层响应的相关性。由此产生的模拟预测的流体压力低于 HM 耦合情景，突出了岩盐溶解对流经岩盐的流体流动的影响。