WELL LOGGING BY RADIOACTIVITY

Abstract

A discussion of the relation of radioactivity curves to physical properties of strata studied, including the influence of the history of the rocks involved. Comparisons are made between the probable areal extent of correlatable horizons in various types of formations, and the ability of various logging methods to distinguish these layers is considered as an index of the geological usefulness of the various logging methods. The possibility of distinguishing altered zones which do not show marked physical differences fom the neighboring rocks (such as faults and unconformities), is discussed, and its bearing on the usefulness of radioactivity logging is considered. Illustrations of the correlating power of radioactivity logs are given. Comparisons with electrical logs and with geological sample logs are shown to illustrate the points discussed. A brief discussion of the development of the radioactivity logging method and of the technique of carrying out field operations is also given.