1963 Paper (C)

A COMPUTER METHOD FOR RETRIEVING FORMATION WATER RESISTIVITY DATA

M. K. Horn

The Pure Oil Research Center Crystal Lake, Illinois

ABSTRACT

The determination of water resistivity, Rw, is an important part of any comprehensive computer system for log interpretation such as COMLOG.4 One method of obtaining Rw is to refer to published and unpublished catalogues arranged by formation and geographic location. These Rw data can be placed on a binary tape in some orderly manner so that formation water resistivities can be efficiently retrieved by computer methods.

In order to develop such a Rw Retrieval system, methods are presented for 1) posting the raw Rw data; 2) sorting the data and arranging it on two scratch tapes; 3) generating the Rw Retrieval tape; and 4) using the Rw Retrieval tape.

The system allows for Rw retrieval of any given geologic formation at the following geographic levels: section, oil field, township-range, county, and region. The program searches for an Rw, starting at the smallest posted geographic division, and continues at consecutively larger division until an Rw is found for the given geologic formation.

The input of the Retrieval system is a series of codes for the designated formation and geographic level(s). Although code numbers are used in this report, a method is shown to use code letters. The output is a retrieved Rw at 70° Fahrenheit. This value may be fed automatically into a comprehensive log interpretation computer system, where it is corrected for zone temperatures; or it may be used separately. The geologic age of the designated formation, determined from the formation code number, is also printed as part of the output.