Underground hydrocarbon storage is a mature technology, born in the early 20th century and very widespread today. The success of this technology lies in its economic efficiency, its safety and, ultimately, its excellent environmental track record.
The market is divided among three techniques: (1) storage in porous media, by far the most widespread technique for storing natural gas; (2) storage in salt caverns, a technique that is suitable for all hydrocarbons; and (3) storage in mined caverns, a technique that is used for liquid or liquefied products.
The market is currently changing. Underground storage facilities are under increasing stress from operators that are seeking to obtain the most from them. Although some storage facilities still have few movements, since they are used for strategic reserves, many storage facilities today have to provide an optimised working volume and higher cycling and deliverability rates than those for which they were created. Monitoring and modelling are helping designers of storage facilities to improve their efficiency. Safety enhancements are the second mechanism by which underground storage facilities are currently being upgraded. This involves design improvements, with the addition of new safety equipment such as fail-safe valves. It also includes the implementation of best practices. Therefore, tools are available that comply with regulatory requirements and meet the economic efficiency needs of storage facilities. The storage facility integrity management system is one of these tools. Diagnosis and tracking of induced seismicity is another example.