NETL is supporting a consortium led by the Illinois State Geological Survey (ISGS) to conduct an evaluation of the carbon storage potential of the Cambro- Ordovician Strata of the Illinois and Michigan Basins, which underlie much of the states of Illinois, Indiana, Kentucky, and Michigan. To date, only cursory studies have been done on the reservoir zones of the carbonate Knox Supergroup, and no field tests or detailed studies have been conducted on the seal potential of the various overlaying shale formations.
During Phase I of DOE’s Regional Carbon Sequestration Partnership (RCSP) research program found that the Mt. Simon Sandstone is a major storage opportunity in the region. It was found that some areas of the Mt Simon is either too deep or of limited permeability to be viable for CO2 storage. Therefore, an evaluation of the storage potential of the Cambro-Ordovician strata, which overlays the Mt Simon, will identify secondary storage opportunities and provide a possible storage resource in the Midwest. The target reservoirs for the Cambro-Ordovician are the porous zones within the Knox Supergroup and the St. Peter Sandstone. The seals of Knox Supergroup include the Maquoketa (Utica) and New Albany shales (Figure 1).
In the early phase of the project, whole core from the MGSC field test in Decatur, Illinois will be collected and a 120 mile 2-D seismic acquisition will be shot in western Illinois. The Kentucky Geologic Survey will conduct a CO2 injection test in Hancock County, Kentucky. These data and existing data will be used to estimate the regional injectivity and storage capacity of the St. Peter Sandstone (Figure 2) and intervals of the Knox Supergroup (Figure 3). Specific studies include modeling the dissolution of CO2 in brine and the interaction with carbonate reservoir rocks, geomechanical tests and petrophysical analyses, an evaluation of mineralization rates, and an analysis of seal faulting potential. The project will conclude with recommendations on the types of data needed to characterize particular reservoirs, which will be incorporated into a best practices manual for assessing the suitability of a Cambro-Ordovician site for CO2 storage. Spatial maps of high- and lowpotential areas of the St. Peter Sandstone and Knox Supergroup will be uploaded to the National Carbon Sequestration Database and Information System (NATCARB).
Carbon capture and storage (CCS) technologies offer the potential for reducing CO2 emissions without adversely influencing energy use or hindering economic growth. Deploying these technologies in commercial-scale applications requires adequate geologic formations capable of (1) storing large volumes of CO2, (2) receiving injected CO2 at efficient and economic rates, and (3) retaining CO2 safely over extended periods. Research efforts are currently focused on conventional and unconventional storage formations within depositional environments such as: deltaic, fluvial, alluvial, strandplain, turbidite, eolian, lacustrine, clastic shelf, carbonate shallow shelf, and reef. Conventional storage types are porous permeable clastic or carbonate rocks that have fluids such as brine, oil, or gas in the natural void spaces of the rocks. Unconventional storage types include unmineable coal, organic shale, and basalt interflow zones1.
The Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) selected 10 projects that received $49 million of DOE funding to characterize promising geologic formations for CO2 storage. The funding was provided by the American Recovery and Reivestment Act of 2009 (ARRA), which was enacted to create new jobs, spur economic activity, and promote long-term economic growth. This research further advances DOE’s efforts to develop a national assessment of CO2 storage resources in deep geologic formtions. These 10 projects are focusing on the regional site characterization of high-potential geologic storage formations. They will assess and develop comprehensive data sets of storage formation characteristics (porosity, permeability, reservoir architecture, cap rock integrity, etc.) to provide insight into the potential for selected geologic reservoirs across the United States to safely and permanently store CO2. An additional $50 million of ARRA funding was provided to augment the work that the existing projects are conducting. This additional funding is allowing these projects to further characterize reservoir geology, identifying additional storage opportunities for industrial CO2 sources. This additional funding is allowing these projects to drill additional and/or deeper wells, collect significantly better log and core data to populate models, collect additional geophysical data, and integrate additional data and conduct more extensive reservoir models.
The overall effort will provide greater insight into the potential for geologic formations across the United States to safely and permanently store CO2. The information gained from this endeavor will further DOE efforts to refine a national assessment of CO2 storage resources in deep geologic formations. Specifically, this project will have a significant impact in further characterizing a new geologic interval that could be used for carbon storage. This should open new areas for geologic storage in southern Illinois, southern Indiana, Michigan, and western Kentucky. It will also confirm the Knox and Maquoketa as secondary confining zones for the Mt. Simon. The project’s contribution to the Best Practices Manual for site characterization will help reduce risks to the geologic storage of CO2 by documenting the uncertainties related to fracturing, injectivity, and geochemical interactions for these specific formations. The data gathered as part of this research effort will be shared with the Regional Carbon Sequestration Partnership’s (RCSP) MGSC, integrated into NATCARB, and utilized for the 4th Edition of the Carbon Sequestration Atlas of the United States and Canada.
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