Dilatancy and tensile criteria for salt cavern design in the context of cyclic loading for energy storage

Abstract

In the current energy transition context, salt caverns are promising for massive energy storage but their design methodology needs to be updated to face the challenge of new operating scenarios. This work proposes a new methodology based on the development of a new rheological model that includes dilatancy and tensile criteria, consistent with the long and short term conditions.To illustrate the difference between the classical and the new methodologies, fully coupled thermo-mechanical numerical simulations of a spherical cavern, filled with either methane or hydrogen, and the surrounding rock salt are performed under various cycling scenarios. Although the two studied gases show distinctive thermodynamic behaviors, the storage of hydrogen does not raise new issues in terms of the cavern design. Concerning the operation history, in addition to the fact that lowering the cycling amplitude limits the development of dilatancy and tension, it is observed that employing a high cycling rate leaves the dilatancy unchanged but intensifies the tension, both in extent and magnitude, even for a small cycling amplitude.