An Integrated Program to Assess Illinois Basin Geological Carbon Sequestration Potential

Robert J. Finley
Illinois State Geological Survey, Champaign, IL

Potential geologic sinks for carbon in the form of carbon dioxide exist within the Paleozoic rock framework of the Illinois Basin, USA. Pennsylvanian coals with low to moderate methane contents, Mississippian and older mature oil reservoirs, and saline reservoirs, such as the Cambrian Mt. Simon Sandstone, are potential targets for geological carbon sequestration. The distribution (two or all three sinks vertically at one location) and characteristics of these options in the Illinois Basin are being assessed through a regional research partnership funded by the U.S. Department of Energy and co-funded by state government, industry, and non-governmental organizations.

The Illinois Basin is a 60,000 sq mi cratonic basin covering most of Illinois and parts of western Indiana and western Kentucky in the midwestern United States. The basin holds >280 billion tons of bituminous coal resources whose market has declined because of moderate to high sulfur content. Deeper or thinner coal seams may be economically unminable and therefore suitable for sequestration. Oil production peaked in the early 1940's. Mature reservoirs now under waterflood are potential targets for CO₂-EOR, but CO₂ miscibility will be in limited to a pressure-temperature defined fairway. Natural gas storage provides insight into Mt. Simon reservoir characteristics in northern parts of the basin, but few wells exist in the south where sequestration may be most favorable. An integrated geological research program was devised and funded to intensively assess sequestration potential based on a large data base held by the state geological surveys of Illinois, Indiana, and Kentucky.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005