Up-to-Date Researches and Future Trends in Underground Gas Storage Facillties: A State of the Art Review

Abstract

The Underground Gas Storage (UGS) facilities are mainly built in hydrocarbon reservoirs (depleted oil & gas fields), in aquifers and also in salt caverns using proven techniques based on the best use of geology and geophysics. Sustained efforts from industrial R&D are devoted to these widely used conventional techniques with the aim to both improve their performances (working gas volume and daily output) and reduce their costs (development, operation and maintenance). Storage facilities in porous and permeable media, oil and gas depleted reservoirs and aquifers account for more than 95 % of the working gas volume capacity world-wide. The technique of storage in salt caverns is also very often used, in particular in the US where the gas market is deregulated, but also in some western European countries where the market on the impulsion of EU is being liberalised. Costs have been divided by two with the development of larger caverns, due to the advances in knowledge of the mechanical behaviour of salt rock and also to the increase in the specific working capacity with the use of higher maximum operating pressures. Techniques aimed to accelerate the availability of salt cavern facilities have been developed, in particular in the US. New techniques, still at the R&D stage, and construction of demonstration units, will offer alternative solutions for underground storage in regions where geology does not permit the development of conventional storage. These are caverns in thin salt layers and lined rock caverns. The expansion of world gas demand will lead to a considerable increase in storage activity in the decades to come, and many new facilities will have to be constructed to meet future needs. This paper also highlights technological innovations in the UGS field.