Definitions, Sources and Explanatory Notes

 Category:   Natural Gas Storage
 Topic:   Underground Storage - All Operators


Key Terms Definition
AGA Eastern Consuming Region All States east of the Mississippi River less Mississippi and Alabama, plus Iowa, Nebraska and Missouri.
AGA Western Consuming Region All States west of the Mississippi River less the Producing Region and Iowa, Nebraska and Missouri.
AGA Producing Region Alabama, Arkansas, Kansas, Louisiana, Mississippi, New Mexico, Oklahoma, and Texas.
Base (cushion) Gas The volume of gas needed as a permanent inventory to maintain adequate reservoir pressures and deliverability rates throughout the withdrawal season. All native gas is included in the base gas volume.
Natural Gas A gaseous mixture of hydrocarbon compounds, the primary one being methane.
Net Withdrawals The amount by which storage withdrawals exceed storage injections.
Storage Additions Volumes of gas injected or otherwise added to underground natural gas reservoirs or liquefied natural gas storage.
Storage Withdrawals Total volume of gas withdrawn from underground storage or from liquefied natural gas storage over a specified amount of time.
Underground Storage Injections Gas from extraneous sources put into underground storage reservoirs.
Underground Gas Storage The use of sub-surface facilities for storing gas that has been transferred from its original location. The facilities are usually hollowed-out salt domes, natural geological reservoirs (depleted oil or gas fields) or water-bearing sands topped by an impermeable cap rock (aquifer).
Underground Storage Withdrawals Gas removed from underground storage reservoirs.
Working (top storage) Gas The volume of total natural gas storage capacity that contains natural gas available for withdrawal.

For definitions of related energy terms, refer to the EIA Energy Glossary.


1979 and prior data from the American Gas Association, Committee on Underground Storage, The Storage of Gas in the United States and Canada. 1980 to current data from Form EIA-191M, "Monthly Underground Gas Storage Report" ; Form EIA-191A, "Annual Underground Gas Storage Report" ; Form EIA-176, "Annual Report of Natural and Supplemental Gas Supply and Disposition" .

  • Background on "Natural Gas Monthly" data
  • Natural Gas Survey Forms and Instructions

  •   Explanatory Notes

  • Net storage withdrawals data through 2006 include underground storage and liquefied natural gas storage. Data for January 2007 forward include underground storage only.
  • Gas in storage at the end of a reporting period may not equal the quantity derived by adding or subtracting net injections or withdrawals during the period to the quantity of the gas in storage at the beginning of the period. This is due to changes in the quantities of native gas included in base gas and/or losses in base gas due to migration from storage reservoirs.
  • Totals may not equal sum of components due to independent rounding.
  • Geographic coverage is the 50 States and the District of Columbia. Prior to January 2013, Alaska data were not included in U.S. totals.
  • Positive net withdrawals indicate the volume of withdrawals in excess of injections. Negative net withdrawals indicate the volume of injections in excess of withdrawals.