ABSTRACT
Today computer techniques dominate the field of log analysis; however, this development has not changed the basic requirements for maximizing information that can be obtained from logs. If quantitative log interpretation is needed, some laboratory analyses of water and rock samples will greatly improve the accuracy of log analysis. The accuracy of qualitative interpretation usually improves with increases in the number of wells that are logged in an area and in the amount of geohydrologic information that is available from other sources. Borehole effects on geophysical logs can be categorized as those produced by the drilling fluids, mud cake, borehole diameter changes, and well-construction materials. From the standpoint of quantitative log analysis, the best procedure is to eliminate from any quantitative use those depth intervals that demonstrate diameter changes that are significant with respect to the borehole-diameter response of the logging tool.
