What is Natural Gas Storage?
Natural gas is stored during periods of lower demand and withdrawn during periods of higher demand. Natural gas storage is most often used to meet seasonal demand.
- Depleted Natural Gas or Oil Fields – The most common storage method is in depleted natural gas or oil fields, typically close to consumption centers. By converting a field into a storage facility, companies can take advantage of existing wells, gathering systems, and pipeline connections. They are the most common sites because of their wide availability.
- Aquifer reservoir – An aquifer is suitable for gas storage if the water-bearing sedimentary rock formation is overlaid with an impermeable cap rock. While the geology of aquifers is similar to depleted production fields, their use in gas storage usually requires more base (cushion) gas and greater monitoring of withdrawal and injection performance. Deliverability rates may be enhanced by the presence of an active water drive.
- Salt caverns – These storage facilities provide very high withdrawal and injection rates relative to their working gas capacity. Base gas requirements are relatively low. The large majority of salt cavern storage facilities have been developed in salt dome formations located in the Gulf Coast states. Cavern construction is more costly than depleted field conversions when measured on the basis of dollars per thousand cubic feet of working gas capacity, but the ability to perform several withdrawal and injection cycles each year reduces the per-unit cost of each thousand cubic feet of gas injected and withdrawn.
Liquefied Natural Gas (LNG) is stored above grounds in storage tanks that are specially designed to maintain the low temperatures required to keep the gas in liquid form.