Writing Computer Program for Display of Stratigraphic Cross Sections Without Having to Create New Database

M. E. Hohn, K. Timberlake

A computer program has been written to access an extant database of stratigraphic tops to draw cross sections, interpolate formation tops between wells, match interpolated tops with driller's tops on new wells, and store new correlations in the database. The program borrows concepts from expert systems to make inferences when the database yields ambiguous, incomplete, or redundant information. When constructing a stratigraphic column, rules that express vertical, geographic, and hierarchical relationships guide the program in ordering units correctly. The program recognized equivalent stratigraphic zones, and can handle situations where a given formation is coded explicitly for one well, but implicitly in the form of members for another well.

Rules can be used to control interpolation of horizons among wells such that the estimated thickness of a unit is calculated either as a distance-weighted average of that in surrounding wells, or difference between two horizons, or proportion of a larger unit.

This program allows new stratigraphic units to be added to the database, and permits geologists to code stratigraphic tops according to their preference. As stratigraphic relationships become better understood with time, new rules can be added for interpreting the database, and the program can be left untouched. Previously, any new formation names required changes to the code of the program that was to display and use these units for correlation.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.