skip to main content

SciTech ConnectSciTech Connect

Title: Maquoketa Shale Caprock Integrity Evaluation

The Knox Project objective is to evaluate the potential of formations within the Cambrian-Ordovician strata above the Mt. Simon Sandstone (St. Peter Sandstone and Potosi Dolomite) as potential targets for carbon dioxide (CO2) sequestration in the Illinois and Michigan Basins. The suitability of the St. Peter Sandstone and Potosi Dolomite to serve as reservoirs for CO2 sequestration is discussed in separate reports. In this report the data gathered from the Knox project, the Illinois Basin – Decatur Project (IBDP) and Illinois Industrial Carbon Capture and Sequestration project (IL-ICCS) are used to make some conclusions about the suitability of the Maquoketa shale as a confining layer for CO2 sequestration. These conclusions are then upscaled to basin-wide inferences based on regional knowledge. Data and interpretations (stratigraphic, petrophysical, fractures, geochemical, risk, seismic) applicable to the Maquoketa Shale from the above mentioned projects was inventoried and summarized. Based on the analysis of these data and interpretations, the Maquoketa Shale is considered to be an effective caprock for a CO2 injection project in either the Potosi Dolomite or St. Peter Sandstone because it has a suitable thickness (~200ft. ~61m), advantageous petrophysical properties (low effective porosity and low permeability), favorable geomechanical properties, an absence of observablemore » fractures and is regionally extensive. Because it is unlikely that CO2 would migrate upward through the Maquoketa Shale, CO2, impact to above lying fresh water aquifers is unlikely. Furthermore, the observations indicate that CO2 injected into the St. Peter Sandstone or Potosi Dolomite may never even migrate up into the Maquoketa Shale at a high enough concentrations or pressure to threaten the integrity of the caprock. Site specific conclusions were reached by unifying the data and conclusions from the IBDP, ICCS and the Knox projects. In the Illinois Basin, as one looks further away from these sites, the formation characteristics are expected to vary. The degree of how well this data can be extrapolated throughout the Basins (regionalized) is difficult to quantify because of the limited amount of data collected on the Maquoketa Shale away from IBDP, IL-ICCS and the Knox projects. Data gathered from the IBDP/IL-ICCS/Knox projects were used to make conclusions about the suitability of the Maquoketa shale as a confining layer for CO2 sequestration. This study indicates that the Maquoketa Shale would be a suitable caprock for a CO2 injection program in either the Potosi Dolomite or St. Peter Sandstone.« less
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Research Org:
University Of Illinois
Sponsoring Org:
Country of Publication:
United States