Geologic Model Building from Non-Standard Core Analysis

Michael Raines
kinder Morgan, Midland, TX

In order to develop a flow simulation model for CO2 flooding the complex geology at the northern end of the SACROC Unit in Scurry County, Texas, Kinder Morgan CO2 Company, L.P. determined that new core information would be required. Therefore a new core was obtained over most of the Pennsylvanian Cisco and Canyon Formation reservoir interval. It was decided that several new techniques would be required to preserve key features of the rock or to provide adequate detail on the core analysis, including the analysis of twelve-inch whole core samples. In order to maximize the value of the new core data for model development and scale-up exercises, a "scale down" exercise was performed on selected samples. These samples were analyzed as twelve inch whole cores, then cut into six inch whole core samples, two inch whole core samples, and a further subset was plugged. Selected analyses were run on each of the smaller steps in order to quantitatively evaluate the effects of sample size. Scale down analysis shows that Kv is sensitive to sample size, and that smaller samples tend to overestimate Kv compared to their longer counterparts, especially in lower permeability ranges (less than 10 millidarcies).