RHOB vs NPHI for six wells in a 4-variable probabilistic clustering analysis using 10 modes (flow units). Each sample is probabilistically assigned to all 10 modes. Here, the samples are color-coded to the mode with the highest (crisp) probability. The ellipses are 4-dimensional ellipsoids projected onto the RHOB-NPHI plane and drawn at ~ 2 standard deviations from the mean. The legend shows the lithologic interpretation for each mode. |
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 A downstream module (MFBG) permits development of profiles for porosity, permeability, and water saturation using the results of clustering plus a mineralogy-based forward modeling procedure. This box model shows matrix and fluid components considered in the modeling process. |
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 This cross section shows the results of a 29-well clustering analysis through the Wilcox Formation in a gas field in Texas. The horizontal axis for each well is cumulative probability with fractional probability assignments (for each mode) stacked left-to-right for each sample. Sands = reds and yellows, siltstones = greens, and shales = grays. |
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