Potential Carbon Sequestration Targets in Saline Reservoirs of Kentucky

Drahovzal, James A., Harris, David C., Nuttall, Brandon C., Solis, Michael P., and Greb, Stephen F.

Kentucky Geological Survey, Lexington, Kentucky

If a carbon-constrained future requires reduced CO₂ emissions, one of the first areas to be affected likely would be the coal-fired power industry. Because of the large volumes of CO₂ produced by Kentucky power plants, sequestration in geologic formations would be an important strategy for meeting air-quality compliance guidelines.

Based on current knowledge, the geologic sequestration option in Kentucky that shows the greatest likelihood for sufficient capacity, safety, and permanency is the deep saline reservoirs. To be effective, these reservoirs would have to be deeper than about 2,500 feet to assure sequestration of supercritical CO₂ and would have to have sufficient injectivity and volume to accept several million tonnes of CO₂ annually from each plant over lifetimes of 30 to 40 years. 

Based on reservoir thicknesses and areal extent, some of the best locations for potential sequestration sites in Kentucky would be along the Ohio River between Cincinnati, Ohio, and Union County, Ky.  In this area, possible sequestration targets include sandstones in the Mount Simon, St. Peter, and Rose Run Formations and vuggy dolostones in the Copper Ridge Formation. Other areas in Garrard, Madison, and Clark Counties, as well as parts of Elliott and Lawrence Counties, Ky., have deep Rome sandstones that are possible sequestration targets.  A porous sandstone in the Middle Run Formation of Hart and Hardin Counties is also a potential sequestration site.

Prior to any large-scale CO₂ injection into these potential target formations, reservoir mineralogy, integrity, heterogeneity, permeability, and structural closure would have to be assessed.