Our study area (Figure 1) is the Dickman field in Ness County, Kansas, a type locality for the geology that will be encountered for CO2 sequestration projects from northern Oklahoma across the U.S. mid-continent. Since its discovery in 1962, the Dickman Field has produced about 1.7 million barrels of oil from porous Mississippian carbonates (Figures 2 and 3) and basal Pennsylvanian sandstone (Figure 4) that locally develops on a regional MIss-Penn unconformity surface. The Dickman field includes a small structural closure at about 4400 ft drilling depth. Project data includes 3.3 square miles of 3D seismic data, 142 wells, with log, some core, and oil/water production data available. Only two wells penetrate the deep saline aquifer. Geological and seismic data were integrated to create a geological property model and a flow simulation grid.
We systematically tested over a dozen seismic attributes, finding that curvature, SPICE, and ANT were particularly useful for mapping discontinuities in the data that likely indicated fracture trends. Recently we have been studying spectral decomposition as a way to detect additional channel details and fracture trends.
Our simulation results in the deep saline aquifer indicate two effective ways of reducing free CO2: a) injecting CO2 with brine water, and b) horizontal well injection. A tuned combination of these methods can reduce the amount of free CO2 in the aquifer from over 50% to less than 10%.
Figure 4. Time slice through 3D amplitude volume at 850 ms (approximate top Miss level) showing clear evidence of incised channel. Geological interpretation along highlighted line on right.