DEPARTURE CURVES AND ELECTRODE FACTORS FOR THE DETERMINATION OF TRUE FORMATION RESISTIVITY FROM ELECTRIC LOGS OBTAINED WITH ROLLER TYPE ELECTRODES IN AIR DRILLED BORE HOLES NOT CONTAINING FLUID

摘要

The purpose of this project was to develop, by use of an electric resistivity-analogue computer and an electrolytic tank model, suitable departure curves and electrode factors from which true resistivities could be determined from the resistances obtained by electric logging of air drilled bore holes with pad type (roller) electrodes,,nMeasurements were made with the resistivity analogue with various arrangements of bed thickness and resistivity to establish the departure curves. Measurements were made with the electrolytic model to determine the electrode factors for three bore-hole sizes and for one, two, and three rollers.