Stacked Log Curves is a graphic display of equivalent log traces from multiple wells, drawn side by side. The Stacked Curve System utilizes digital log data residing in the user's data base. The log traces can be plotted at regular intervals or spaced according to the geographic location of the wells. Interactive graphics technology is the ideal vehicle for this application.

The uses of Stacked Log Curves range from quality control to exploration. Typical data problems easily detected by this display are improper digitizing scales, misidentified curves, and data gaps. Simple statistical and mathematical functions may be applied to the curves, permitting computation of zero shift and sensitivity correction factors. These values are used for curve normalization to compensate for differences in logging tools and borehole environments.

Varying the spacing between wells will produce displays ranging from a geologic cross section to a pseudo seismic section. Markers can be picked, corrected, and displayed for all wells, thus assuring accuracy in tracing horizons across long distances. By plotting computed curves such as porosity and lithology percentages, porosity pinch-outs and facies variations can be recognized. Overlaying Stacked Log Curves of appropriate traces can single out zones of interest. After converting from depth to a time scale, these plots can be directly compared with the seismic section.

The raw log data, the corrected and normalized log data, and the marker picks are stored in the computer for further analysis and mapping.

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