Inversion of creep parameters and their application in underground salt cavern energy storage systems for enhancing wind power integration

Abstract

While the development of wind energy presents great potential and opportunities, the high level of uncertainty inherent in wind farms also poses considerable challenges for operators, especially when it comes to participating in the energy market. The intermittent and unpredictable fluctuation characteristics of wind power generation may cause significant deviations in the frequency and voltage of the grid, which pose a certain threat to the stability of the grid and power quality and need to be mitigated by advanced energy storage solutions. Salt caverns, these geological structures deep in underground space, are widely used in oil and gas storage, compressed air energy storage(CAES), and other projects around the world. In the operation of underground salt caverns as storage, there is no effective technical means to monitor the deformation of deep caverns in real-time. Therefore, developing a high-precision real-time prediction method for cavern volume deformation is of great significance for the safety assessment during the underground salt cavern operation. In this context, this paper proposes a comprehensive technical approach to meet the needs of real-time monitoring of the cavern status, including volume changes, in the intelligent construction of underground salt cavern facilities in China. Firstly, through the shut-in pressure test of the brine well, the volume shrinkage of the cavern during the monitoring period is obtained, and the creep parameters of the salt rock strata in the regional salt mine are inversely derived. Secondly, for a typical cavern in operation in this region, the creep deformation is predicted using numerical simulation methods. By analyzing the cavern volume deformation under different pressures, an empirical equation for cavern volume deformation is established. Finally, by combining the volume changes obtained from sonar tests conducted during the operation of the cavern, the accuracy of the simulated results and the theoretical model derived from the inverted creep parameters is verified. The real-time analysis method for cavern volume deformation developed from this research will be applied to the intelligent construction of underground salt cavern facilities, ensuring safe and controllable operation management of the storage facilities.

Keywords

• Salt cavern
• Creep
• Cavern measuring with sonar
• Wind power integration
• Cavern volume deformation
• Compressed air energy storage