Subsurface Storage and Disposal in Illinoisa

Abstract

ABSTRACTThe storage of both liquids and gases in underground strata has become rather common in Illinois.The problem of disposal of fluid industrial wastes has caused greatest concern, especially for the possible effects on ground‐water quality. Necessary precautions have been established in the requirements of the Illinois Environmental Protection Agency (IEPA) which has authority to control, prevent, and abate pollution of streams, lakes, ponds, and other surface and underground waters in the State. Before any construction can begin on storage in subsurface strata, a permit must be secured from the IEPA. Eight basic design policies have been adopted that have to be met before a construction permit will be issued.Sandstone, limestone, and dolomite are the basic lithologies most commonly considered as potential disposal reservoirs in Illinois. From well cores of such formations, essential laboratory studies are conducted defining the rate of fluid movement, porosity, and permeability of the rock and the pressure distribution within the aquifer.Plugging of the injection horizon is the most serious cause of damage to a fluid injection system and results from the forming of an impermeable deposit on the well bore or plugging in the formation itself. In either case the plugging may result from a number of listed causes.To date there have been four industrial waste disposal wells in Illinois. Variation in conditions is illustrated by these cases of disposal wells that have been authorized by the State.The first practical use of underground gas storage in Illinois was at Waterloo in 1950. Since then, the number of projects and their capacities have grown continuously. At the present time there are 24 underground gas storage projects. Gas injection pressures must be kept below the fracturing pressure of the caprock. In underground gas storage reservoirs in Illinois, injection pressures of approximately 0.55 psi per foot are often used.Secondary recovery by water flooding accounted for 73.4 percent of the total oil production in Illinois during 1968. In that year there were 880 active projects in Illinois with 13,107 water injection wells that injected 2581 million gallons of water.