Geomodel
Development and Simulation Studies for Possible Carbon Dioxide Sequestration
and Enhanced Coalbed Gas Recovery Beneath a Major Kansas City Landfill
S.
Bhattacharya1,
K. D. Newell1, T. R. Carr1, and J. G. Blencoe2.
(1) Kansas Geological Survey, University of Kansas, Lawrence, KS, (2) Oak Ridge
National Laboratory, Oak Ridge, TN
Pennsylvanian
coal and gas shale units, which underlie the Johnson County Landfill serving
Kansas City, respectively record maximum as-received gas contents of 79 scf/ton
(Bevier coal, 570-ft depth) and 22 scf/ton (Anna Shale, 421 ft). In-place gas
in five coals and three shales beneath the landfill is calculated to be 986
mcf/acre. Isotopic and chemical analyses of desorption gases indicate that they
are of mixed biogenic/thermogenic origin. Proximate analyses indicate the coals
are high-volatile C to B bituminous ranks. The coals and gas shales are
undersaturated with respect to their gas content, and the degree of saturation
decreases with depth.
Daily production
of landfill gas from the Johnson County Landfill is approximately 2.5 mmcf, of
which 50% is methane (CH4) and 50% is carbon dioxide (CO2)
and non-methane volatile organic compounds. About 4.5 years of landfill CO2
production can be expected to be sequestered under the 960-acre site assuming
that CO2 can be imbibed on a 2:1 ratio compared to gas originally
adsorbed.
A multi-layer
3D-simulation study was carried out on a five-spot (one injector, four
producers) pattern located on 40 acres to evaluate the volumes of CO2
adsorbed and CH4 produced, and respective breakthrough times. In
preparation for a possible pilot demonstration, Monte Carlo simulation
incorporating uncertainties in petrophysical parameters and recoveries was
conducted for net-present-value (NPV) estimation. This proposed value-added
model of CO2 sequestration is expected to benefit unconventional gas
production by increasing the rate and amount of CH4 desorbed from
the gas-bearing coal and shale units.
AAPG Search and Discover Article #90067©2007 AAPG Mid-Continent Section Meeting, Wichita, Kansas