Computer Program for Stratigraphic Correlation of Devonian Shales in Appalachian Basin

K. Timberlake, M. Hohn, S. Kite, M. C. Behling

A computer program has been written to perform graphic and computational functions related to stratigraphic correlation. Stratigraphic information is retrieved from a data base and used to interpolate formation tops between wells. A stratigraphic cross section can then be drawn on a graphics terminal. Kriging is employed in the interpolation to control smoothing. The user can stipulate which wells are included in the cross section, or ask for wells near a specific location or near a specific well.

The cross section and other output from the program can be used to determine pay zones that were not correctly interpreted by a driller, to confirm a stratigrapher's correlations, and to find anomalous information in the data base. Estimated tops can be stored in the data base from within the program. Additional graphic activities include drawing a map of well locations and a graphic comparison of a strip log drawn from user-entered driller's lithologic tops and the interpolated tops. The driller's tops and interpolated tops can be matched by the program. The user can choose to turn off the graphics and just interpolate tops for each well on a list provided by the user.

If some tops are known in a well, these can be used to interpolate the remaining tops. The base of the Berea Sandstone is commonly used. Accuracy of the interpolations increases as more known tops are used.

The program is written in FORTRAN, and uses PLOT 10 Graphical Kernal System. It runs on a VAX 11/750. A Tektronix 4207 color terminal is needed unless the user opts for no graphics.

AAPG Search and Discovery Article #91031©1988 AAPG Eastern Section, Charleston, West Virginia, 13-16 September 1988.