--> Abstract: CO2 Sequestration in Gas Shales of Kentucky, by Brandon C. Nuttall, James A. Drahovzal, Cortland Eble, and Marc Bustin; #90039 (2005)

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CO2 Sequestration in Gas Shales of Kentucky

Brandon C. Nuttall1, James A. Drahovzal1, Cortland Eble1, and Marc Bustin2
1 Kentucky Geological Survey, Lexington, KY
2 University of British Columbia, Vancouver, BC

Economic growth depends on the availability of energy. Efficiency and alternate energy sources will reduce emissions from fossil fuel combustion, but carbon capture and storage are required to meet goals of stabilizing CO2 in the atmosphere. Saline reservoirs, unmineable coals, and depleted oil and gas reservoirs are candidate sequestration sites. Continuous, low permeability, fractured, organic-rich gas shales represent another alternative. Devonian shales underlie approximately two-thirds of Kentucky. These shales are the source and trap for large quantities of natural gas. Enhanced natural gas recovery may be possible as stored CO2 displaces methane.

Drill cuttings and cores from Kentucky, West Virginia, and Indiana were sampled and adsorption isotherms collected. Sidewall core samples were analyzed for their potential CO2 uptake and resulting methane displacement. Average random vitrinite reflectance data range from 0.78 to 1.59, the upper oil to wet gas and condensate maturity range. TOC ranges from 0.69 to 4.62 percent. CO2 adsorption capacity at 400 psi ranges from 19 to 86 standard cubic feet per ton of shale.

Estimates based on these data indicate a sequestration capacity of 5.3 billion tons CO2 in the Lower Huron Member of the Ohio shale of eastern Kentucky and as much as 28 billion tons total in the deeper and thicker portions of the Devonian shales in Kentucky. Should shales prove to be a viable geologic sink for CO2, their extensive occurrence in Paleozoic basins across North America would make them an attractive regional target for economic CO2 storage and enhanced natural gas production.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005