Subsurface play elements were derived from datasets and are generally first order attributes of geologic units. Subsurface storage formations and confining units are the fundamental technical elements required for a viable carbon storage project.
Subsurface play elements were organized into three subgroups:
- Storage – Play elements related to storativity and volumetrics
- Containment – Play elements related to secure long-term storage
- Water – Play elements related to groundwater quality and protection
Mt. Simon Sandstone Storage Complex
For the Mt. Simon Sandstone Subsurface CRS Map, decreasing suitability to the north is primarily controlled by declining formation-water salinity and, to a lesser extent, decreasing depth. In southwestern Illinois, suitability decreases where the Mt. Simon thins and becomes absent due to non-deposition or erosion. In southeastern and southernmost Illinois, areas of reduced suitability occur adjacent to known faults. Within the broad suitable to most suitable fairway across the southern two-thirds of the state, localized zones of lower suitability are largely associated with a high density of legacy wellbores that penetrate the confining unit or with the presence of saline springs.
St. Peter Sandstone Storage Complex
For the St. Peter Sandstone Subsurface CRS Map, similar to the Mt. Simon Sandstone, decreasing suitability to the north is primarily controlled by declining formation-water salinity and decreasing depth. In southeastern and southernmost Illinois, areas of reduced suitability occur adjacent to known faults. As a result, the suitable to most suitable fairway is narrower in the southern half of the state, with localized zones of lower suitability largely associated with a high density of legacy wellbores that penetrate the confining unit or with the presence of saline springs.