The Cambro-Ordovician strata form the most important carbon sink available for the sequestration of CO (sub 2) in the heavily industrialized Midwest of the United States. In the Illinois Basin, the three most significant suitable for sequestration are the Cambrian Mt. Simon Sandstone, the Cambrian carbonate intervals in the Knox Group, and the Ordovician St. Peter Sandstone. The evaluation of these formations was based on data collected from the US DOE-funded Illinois Basin -- Decatur Project being conducted by the Midwest Geological Sequestration Consortium (MGSC) in Macon County, Illinois. All three formations have significant potential. The Knox formation is composed of interconnected solution cavities that make CO2 plume prediction difficult. The St. Peter Sandstone is a potential sink but, at 52 m (170 feet) thick, it has less storage capacity than the Mt. Simon Sandstone. The Mt. Simon Sandstone is over 487 m (1600 feet thick) in the Decatur area with average porosities of 22% and permeabilities of 200 mD. However, individual intervals can have porosities as high as 28% and permeabilities of over a Darcy. Few wells have been drilled through these Cambro-Ordovician saline reservoirs because there are no recoverable hydrocarbons; therefore, seismic reflection data integrated with regional geologic models are absolutely necessary for evaluating potential sites and characterizing reservoirs with only one or two wells. Regional seismic profiles across the Illinois Basin were used to define areas of high and low risk for sequestration. Areas have been designated as high risk if the Mt. Simon Formation is thin or non-existent as a result of Precambrian topography or if it is a structurally complex area with extensive faulting. Seismic and regional well data suggested that the saline formation at Decatur, Illinois is an excellent sink for CO (sub 2) . Seismic acquisition at the Illinois Basin -- Decatur Project has been challenging given that the site is located in close proximity to two industrial plants, the city suburbs, and the city reservoir. Site access was limited due to the surrounding infrastructure, and high levels of noise came from the commercial plants in the area, high-line electrical interference along with heavy industrial traffic. Two three-dimensional (3D) surface seismic reflection surveys were acquired at different time periods and the combined processed data shows significant noise reduction. Based on the regional data two wells were drilled to the granitic basement. These wells were used as a ground truth for advanced attribute analysis including seismic inversion. The seismic inversion analysis resulted in a 3D model of the porosity distribution that is being used to build the geologic model and complete reservoir simulations of the CO (sub 2) plume.
|Original language||English (US)|
|Title of host publication||American Geophysical Union Fall Meeting|
|Place of Publication||Washington, DC|
|Publisher||American Geophysical Union|
|State||Published - 2011|
Leetaru, H. E., Coueslan, M. L., Brown, A. L., & Finley, R. J. (2011). Successful integration of seismic reflection data for evaluating the sequestration potential of the Cambrian and Ordovician strata of the Illinois Basin, USA. In American Geophysical Union Fall Meeting (Vol. 2011). American Geophysical Union.