SUITABILITY OF THE ST. FRANCOIS CONFINING UNIT AS A CAPROCK ABOVE CO2 INJECTION ZONES IN MISSOURI
At the City Utilities Southwest Power Plant (Greene County, Missouri) we cored the St. Francois confining unit and completed shut-in packer tests in 6.5-m intervals spanning that unit. Visual and geophysical logging show that these strata are ~ 50% shale, and that interbedded carbonates (both limestone and dolomite) generally consist of dense, discrete clasts encased within shale. These characteristics are visually identical to those in mineral-exploration cores throughout southwest Missouri. The shut-in tests give (radial) hydraulic conductivities generally ranging from approximately 10-12 - 10-14 m/sec, and provide a (calculated) vertical hydraulic conductivity of ~10-13 m/sec at the local scale. Thus, any significant leakage across this confining layer over short time frames would have to be along discrete avenues such as fault/shear zones.
This material is based on work sponsored by the Department of Energy National Energy National Energy Technology Laboratory under Award Number DE-NT0006642 to City Utilities of Springfield, MO and Award Number DEFG2610FE0001790 to Missouri State University.