Design of salt caverns for the storage of natural gas, crude oil and compressed air: Geomechanical aspects of construction, operation and abandonment

Abstract

AbstractSalt cavities for the storage of natural gas in bedded or domal salt structures are an important element of current and future energy supply management. In Germany, the mechanical design of salt cavities has a history of more than 35 years. This paper gives a personal view of current salt cavity design. It discusses the geomechanical characteristics of storage cavities and principle safety demands for their design as well as recent design concepts and methods for providing geotechnical proof of safety with specialized criteria, limit values and safety margins. In view of the uncertainties inherent in the design of geotechnical mechanical structures, monitoring of excavation and operation are essential parts of underground geotechnical constructions. A new monitoring software code is presented that will help both to document that past and to plan future cavern operation. Cavern abandonment is an object of current research, especially the basic understanding of mechanisms acting or becoming active at elevated fluid pressures (gas or brine) at the level of primary (lithostatic) rock mass pressures. This paper presents some basic knowledge and a computer code for analysing the long-term behaviour of sealed liquid-filled salt cavities with simulation of pressure build-up, infiltration and following seepage flow.