Gas Storage Basics
The use of underground natural gas storage facilities is almost as old as the development of long-distance transmission lines. The first high-transmission lines began operations in 1891 with successful construction of two parallel 120-mile, 8-inch diameter lines from fields in northern Indiana to Chicago. The first successful gas storage project was completed in 1915 in Welland County, Ontario. The following year, operations began in the Zoar field near Buffalo, New York.Underground natural gas storage can be used to effectively balance a variable market with a nearly constant supply of natural gas provided by the pipeline system. Storage fields are the warehouses that give a ready supply of natural gas that can serve a market with high peak demands in warm or cold weather.
Generally, more natural gas is used during the winter because many homes are heated by natural gas. Therefore, natural gas is injected into storage fields during the summer (April - October), and withdrawn in the winter (November - March). However, recent increases in the amount of gas-fired power generation have resulted in daily variances in the amount of natural gas being used. Natural gas in storage also serves as insurance against any unforeseen accidents, natural disasters, or other occurrences that may affect the production or delivery of natural gas.
Natural gas storage uses a confined geologic formation to temporarily store and provide efficient and dependable supplies of natural gas to consumers, businesses and utilities. There are over 400 natural gas underground storage facilities in operation in the United States today with the capacity to store 3,900 Bcf. Approximately 86% of these facilities utilize depleted reservoirs. The remaining 14% utilize either salt caverns or aquifers.
There are currently fifteen natural gas storage fields operating in Louisiana. Eight of the projects are in depleted gas fields while the other seven are salt cavern storage facilities.
Depleted reservoir storage utilizes a depleted underground natural gas reservoir that originally contained oil and/or gas. Gas is injected back into the depleted reservoir in order to re-fill the reservoir. The withdrawal process for the gas in storage is similar to the process originally used to produce gas from the reservoir in the first place. The conversion of a depleted gas reservoir for storage use traditionally involves drilling many new wells that enable a more rapid withdrawal of gas than was originally used to deplete the reservoir. Because these formations previously contained oil or gas for millions of years, storage developers and operators know that they can safely and successfully store gas today.
Types of Underground Natural Gas Storage Facilities
