Contour Cross Plots

Contour crossplots are used to summarize multi-well log data. 

Basically, as more and more individual well data is crossplotted on one crossplot, the data trends tend to look like a shot gun blast. 

By contouring the shotgun blast the internal structure of the data being crossplotted can be more fully examined.

shotgun blast example

The crossplotted data is gridded and then contoured. 

The contours are contours of frequency occurence of the data being crossplotted.

contoured shotgun blast



Contour crossplots are extremely important when applied to the analysis of normalized well log data from multiple wells.  As one becomes a student in the analysis of the trends of various crossplot combinations of well log data in combination with related geological data, applications such as the example below become logical extensions of the well log analyses. 

In the example below, when crossplotting normalized density porosity vs. normalized gamma ray data, poorly sorted sandstone data always falls as illustrated on the crossplot.  The map adjacent to the crossplot shows the apparent thickness of the poorly sorted data as outlined by the polygon on the crossplot. The 'channel like' trend displayed on the map substantiates the poorly sorted interpretation based on the contour crossplot.

This example, is an example of the Colony sand distribution based on the interpretation of digital well log data from approximately 200 wells from the Cold Lake Area of Alberta

polygon mapping application

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