ASSESSING THE CO2 STORAGE CAPACITY IN THE CENTRAL APPALACHIAN BASIN: RESULTS OF THE KENTUCKY GEOLOGICAL SURVEY TEST WELL, CARTER COUNTY, KENTUCKY

The Kentucky Geological Survey drilled the 1 Hanson Aggregates well in northern Carter County, Kentucky, to assess the CO₂ storage capacity of the Cambro-Ordovician section in the central Appalachian basin, north of the Rome Trough. Storage capacity was evaluated for deep saline reservoirs in the Middle Cambrian Mount Simon and Maryville Sandstones, and Late Cambrian Copper Ridge Dolomite and Rose Run Sandstone. Sealing capacity of overlying Middle Ordovician shales was evaluated for ensuring long-term CO₂ storage in the deep subsurface. The well was drilled to a total depth of 4835 ft, penetrating the entire Paleozoic section and 120 ft of Neoproterozoic Grenville granite gneiss. Steel casing was cemented to the surface at 350 ft and 2944 ft to isolate the deep wellbore from the near-surface groundwater aquifer. Eight cores totaling 453 ft and 30 rotary sidewall cores were cut, and an extensive suite of geophysical logs, including imaging logs, were recorded in the borehole. Water lost during drilling to the formations below casing at 2944 ft is indicative of the under-pressured, below hydrostatic pressure, reservoirs typical of the deep subsurface in Kentucky. Laboratory analysis was performed on 86 core plugs to determine porosity and permeability, triaxial rock strength for 13 core plugs, capillary entry pressures for 9 shale core plugs, and 59 thin sections of sandstone and carbonate reservoir rocks. From these data, three intervals were selected for formation water samples, step-rate pressure tests to determine in situ rock strength, and reservoir porosity and permeability parameters: the Mount Simon–Maryville section, middle Copper Ridge, and Rose Run. Preliminary reservoir heights estimated for the three test intervals, at the 7% industry-standard porosity cutoff, are similar: 23 ft net in the Mt. Simon–Maryville, 28 ft net in the middle Copper Ridge, and 27 ft net in the Rose Run. These results suggest that reservoir properties in these strata are sufficient for CO₂ storage and confinement, and, by correlation, applicable to the region north of the Rome Trough in central Kentucky, the Ohio River industrial corridor, and on into central Ohio.