New Approach for the Classification of Rock Typing Using a New Technique for Iso-Pore Throat Lines in Winland's Plot

Abstract

Abstract The new approach aids in assigning the location of the iso-pores throat lines on Winland's plot. The approach was verified with a total number of conventional core analysis data that exceeded 1960 data points from three different sandstones reservoirs. The utilization of the R35 plot will guide through the number of rock types and their corresponding pore-throat ranges which will aid us in minimizing the human error while optimizing these iso-pore throat lines locations. Winland's equation is one of the powerful methods used to utilize the reservoir properties to classify the number of rock types in a reservoir. Winland's plot is a semi-log plot of permeability versus porosity overlaid by the iso-pore throat lines, R35. These iso-pore throat lines could be shifted based on the reservoir characterizations. The simplicity of the new approach makes it a must step in every analysis prepared on Winland's plot. Plotting a semi-log of sorted R35 versus serial numbers; then, observing the change in the slope of the line, each change in the slope indicates a new rock type. When applying this approach on three different sandstone reservoirs, Reservoir A; showed seven detailed rock types. Eight detailed rock types were indicated in reservoir B and nine detailed rock types were indicated in reservoir C. It also gives the engineers and petro-physicists the choice of combining similar rock types together resulting in an optimum rock system. These rock types were confirmed with the static models and proves the solidity of the new approach in categorizing the optimum number of rock types. The value added in the new approach aids in the determination of where these iso-pore throat lines should be placed to give the optimum classification on the rock typing, as a substitute to the current subjective approach. An automated process was programmed to assist the user in the classification of the rock types and it automatically displays the values for any given reservoir.