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Nuttall, Brandon C.1, James A. Drahovzal1, Cortland F. Eble1, R. Marc Bustin2 
(1) Kentucky Geological Survey, Lexington, KY 
(2) University of British Columbia, Vancouver, BC

ABSTRACT: Analysis of the Devonian Black Shale in Kentucky for Potential Carbon Dioxide Sequestration and Enhance Natural Gas Production

Injecting CO2 into organic-rich shales is an untested carbon sequestration strategy. Devonian black shales underlie approximately two-thirds of Kentucky. These shales are the source and trap for large quantities of natural gas. Most of this natural gas is adsorbed on clay and kerogen surfaces, analogous to methane storage in coal beds. In coals, it has been demonstrated that CO2 is preferentially adsorbed, displacing methane. Black shales may similarly desorb methane in the presence of CO2
Current research is investigating the black, organic-rich Devonian shales as a potentially significant geologic sink for CO2. Drill cuttings from the Kentucky Geological Survey Well Sample and Core Library are being sampled. CO2 adsorption isotherms are being collected to determine the gas-storage potential of the shale and to identify optimum shale facies. Sidewall core samples have been acquired to investigate specific black-shale facies, their potential CO2 uptake, and the resulting displacement of methane. Advanced logging techniques (ECS) are being investigated for possible correlations between adsorption capacity and geophysical log measurements. 
Initial estimates 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 the black shales of Kentucky 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 #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.