Assessing the Reservoirs and Seals Potential of the Cambro-Ordovician Knox Group in the Illinois Basin for CO2 Sequestration
Carbon sequestration is becoming an important strategy worldwide for continued utilization of fossil fuel to meet the world’s energy demand. Among various methods for carbon sequestration, injection in deep saline formations appears to provide the safest method for storing large volume of CO2. Porosity and permeability, thickness, lateral extent, and depth of reservoir rocks and the presence of multiple impermeable seals are among factors that control feasibility of CO2 sequestration in deep saline formations. To determine lateral and vertical lithologic variations of the rocks within the Knox Group that could serve as reservoir or seal for CO2 storage, a number of deep wells from the Illinois Basin were examined in detail. Well cuttings and available cores of these wells and samples from exposures in west-central Missouri were studied in detail and the results were compared with geophysical logs. The results show that the Knox Group in the Illinois Basin and adjacent Midwestern regions may be an attractive target for CO2 sequestration because these rocks are 1) laterally extensive, 2) consist of some porous and permeable dolomite and sandstone intervals, and 3) contain abundant impermeable shale and carbonate seals. The rocks of Knox Group, because of their thickness (up to 6000 feet), widespread occurrence, and depth (more than 7000 feet) in deeper part of the basin, can provide a significant additional reservoir for CO2 storage. Furthermore, the porous rocks of the Knox Group can also capture any CO2 that may leak from the underlying Mt. Simon Sandstone, currently a major target reservoir for CO2 sequestration in the U.S. Midcontinent.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California