Geophysical logging (Gamma ray, Resistivity, Sonic, Optical/acoustic Televiewer, etc.)

Geophysical logging is the process of recording and observing measurements of physical properties made in wells or holes. Probes that measure different properties are lowered into the borehole to save data that are graphically showed as a geophysical log. Multiple logs typically are collected to take advantage of their synergistic nature (much more can be learned by the analysis of a suite of logs as a group than by the analysis of the same logs individually). Logs are used in ground-water and environmental investigations to get information on well construction, rock lithology and fractures, permeability and porosity, and water quality.