周期性荷载及温度作用下盐穴氢气储库围岩损伤与渗透演化机制研究

盐穴大规模储氢是实现可再生能源调峰的重要手段。利用我国层状盐岩储氢时，盐穴围岩受到复杂的周期性应力、温度及高压氢气渗透的共同作用，而氢气比天然气分子更小，更易渗透和扩散，储库的风险更大，认清围岩的损伤与渗透演化规律是实施安全储氢的前提和关键。对此，本项目紧密围绕层状盐岩盐穴氢气储库围岩的损伤与渗透演化机制这一关键科学问题开展系统研究。首先，进行层状盐岩化学稳定性及封闭指标分析，揭示地层对氢气的可储性及围岩封闭性。其次，实施周期性应力-温度作用下的层状盐岩损伤演化的宏细观研究，建立其力学耦合模型与破坏判据。然后，开展不同周期性氢气压气作用下的层状盐岩渗透试验，提出渗透演化的理论模型与渗漏致灾标准。最后，结合模型的二次开发及不同调峰工况的盐穴储氢模拟，探明各工况下围岩的长期稳定性与密闭性，形成储氢的运行方案优化与围岩安全调控理论。成果将为我国盐穴大规模储氢的选址、设计及运营等提供指导。

Large-scale hydrogen storage in the salt caverns is an important way to achieve peak adjustment of renewable energy. In the case of hydrogen storage in the cavern of bedded salt rock in China, the wall rock is affected by complex periodic stress, temperature and high-pressure hydrogen permeation. But hydrogen has smaller molecules than natural gas, and is easier to seepage and diffuse, so the salt cavern face much greater risk and difficult for hydrogen storage. The investigation of the damage and permeation evolution characteristics of cavern wall rock is the prerequisite and key issue to ensure the safety for hydrogen storage in salt cavern. For this reason, this project focuses on the key scientific problem of damage mechanism and permeation evolution of cavern wall rock of hydrogen storage in bedded salt rocks. Firstly, the mineral chemical stability and sealing index of the bedded salt rock will be analyzed to reveal the hydrogen storability of the formation and the sealing property of cavern wall rock. Secondly, the macroscopic and microscopic study of the damage evolution of bedded salt rocks under the action of periodic stress-temperature will be carried out, and the coupled mechanical model and failure criteria would be established. Thirdly, the permeation test of the bedded salt rock under different periodic hydrogen pressures will be carried out, and the theoretical model of permeation evolution and the criteria of leakage would be put forward. Finally, combined with the secondary development of the models and the simulation of hydrogen storage under different peak adjustment conditions, the long-term stability and tightness of the wall rock of hydrogen storage cavern under different working conditions will be verified, and the optimization method of the operation scheme of hydrogen storage and the safety control theory of wall rock would be formed. The results will provide theoretical guidance for the site selection, operation and safety evaluation of large-scale hydrogen storage in the salt cavern in China.