Evaluation of Electric Well Logs from Appalachian Basin with Small Microcomputer System

Eberhard Werner

Several computer-based packages for interpreting electric well logs are available. These programs serve well for those whose primary duty is to interpret a great variety of logs. However, these are often not cost-effective for the independent geologist who is only occasionally required to interpret logs or for the academic researcher with little funding. A low-cost system to aid in the interpretation of the typical log suite taken in Appalachian basin wells consists of a set of basic programs run on a small personal computer provided with a digitizer and pen plotter. For the most common situation found in the basin--the air-drilled well--the only logs normally run will be gamma-ray, induction, neutron, and bulk-density. Varying quality of these logs may require some exper mentation in the values used in the equations for reserve calculations. An additional problem that must be addressed in the evaluation system is that of shaly sand. Features were incorporated into the software to address these problems. Log data may be entered from strip charts of any scale through the digitizer, or values may be read and entered manually via the keyboard. Various equations and constants may be chosen from a set of menus, and all or part of the log data processed. Saving the raw data on disk allows recalculation using different parameter values. Results derived from the calculations include saturations of water, oil and gas, corrected porosity, shale to sandstone ratios, bulk water volume, and potential in-place reserves. Results may be printed or plotted in various form ts.

AAPG Search and Discovery Article #91041©1987 AAPG Eastern Section Meeting, Columbus, Ohio, October 7-10, 1987.