Salt caverns history and geomechanics towards future natural gas strategic storage in Brazil

摘要

Salt rock distinguished properties such as creep and tightness make them useful as underground disposal and storage media. This work presents a comprehensive review of salt caverns history and fundamentals of their mechanical behavior. Emphasis is given to salt creep and dilatancy. Following, a methodology for numerical simulation of mechanical behavior of salt caverns is compiled. Transient pressure simulates the constructive period by solution mining and the operation period, during which gas pressure cycles apply. A synthetic case study is performed to demonstrate the methodology. Stress- and strain-based engineering-practical criteria evaluate the global integrity of the cavern. Results show that the cavern wall does not undergo microcracking, remaining tight. This integrity condition is fundamental for underground storage safety. Moreover, strain-related engineering criteria are satisfied in such a way that cavern usability is assured over its lifespan.