Underground storage of natural gas in Illinois--1973

Natural gas is stored in underground reservoirs at 37 locations in Illinois. These reservoirs contain more than 580 billion cu ft of gas, about one-third of which is working gas and two-thirds is cushion gas. Potential usuable capacity of these reservoirs is estimated to be 1.2 trillion cu ft. At 11 of the storage projects, gas is stored in depleted, or partially depleted, gas reservoirs. One depleted oil reservoir is used for storage, and in the remaining projects, gas is stored in aquifers that originally contained no hydrocarbons in commercial quantities. At 4 locations, 2 reservoirs at different depths are in various stages of exploration, testing or development for storage. Two projects have been abandoned. Rocks of all systems from Cambrian to Pennsylvanian are used for storage of gas in Illinois. However, most of the storage volume is in sandstone aquifers of Cambrian and Ordovician age. (50 refs.)