Tuesday, February 8, 2011

Dickman Project Overview

The goals of this DOE-funded project were to develop innovative 3D seismic attribute technologies and workflows to assess the structural integrity and heterogeneity of subsurface reservoirs with potential for CO2 sequestration. Our specific objectives were to apply advanced seismic attributes to aide in quantifying reservoir properies and lateral continuity of CO2 sequestration targets.

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 1. Dickman field site and description of available data.

Figure 2. Annotated type log for Dickman project area (black circle in Fig. 1).

Figure 3. Chart to the left is the stratigraphic rank accepted by the Kansas Geological Survey (Sawin et al., 2008). The chart to the right shows correlation to Dickman local stratigraphic units, with higher confidence correlations in bold. The blue vertical bar indicates the target strata for Dickman research.

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.

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