Assessment of
Geologic CO2 Sequestration at a Proposed FutureGen
Site in Kentucky
Drahovzal, James A.1,
David C. Harris1, Stephen F. Greb1, Brandon C. Nuttall1
(1) Kentucky Geological Survey, Lexington, KY
A reclaimed surface coal mine in western Kentucky was proposed as a site
for FutureGen, an industry-government effort to build
a near-zero emissions power plant. Though the site was not selected for FutureGen, an integrated-gasification-combined-cycle plant
is planned for an adjacent site and, as at the FutureGen
plant, geologic CO2 sequestration may take place there in the
future. The site was initially chosen because of its attractive infrastructural
and surface attributes; however, it also lies within a part of the southern Illinois Basin that has significant
geologic sequestration potential. Several potential sequestration horizons were
assessed at the site.
The Mount Simon Sandstone, a significant
regional sequestration target, was only minimally assessed, and not considered
a target because of its excessive depth, suspected thinness, and uncertain
permeability at the proposed site. The St. Peter Sandstone was more carefully
assessed. A permeable zone in the Knox Supergroup,
however, was chosen as the primary sequestration target, based on a 54-foot-thick
zone that averaged 9 percent porosity in a nearby well. In Kentucky, the Knox is a
hydrocarbon producer and has been used for waste injection at two locations.
The target zone at the site lies about 7,380 feet beneath the surface and is at
the crest of a northeast-oriented, elongate dome with 100 to 200 feet of
closure. With ultimate injection of up to 50 million tonnes
of supercritical CO2, plume migration would progress northwest along
the crest of the structure, eventually covering an area of approximately 50
square miles. Seals include the overlying Knox itself, Trenton carbonates, the
Maquoketa Shale, and the New Albany Shale. Several faults in the vicinity would
require monitoring to assure seal integrity.