What is Geophysical Logging?
Geophysical logging is a method by which cylindrical probes are lowered into the borehole on a cable. In the core of the cable are wires that transmit a signal generated in the probe back to the surface as the probe is moved vertically in the well bore. At the surface the signals are processed by a computer and translated into various logs depending upon the type of probe being run in the borehole. A wide range of borehole information can be obtained from various probes that are currently available. Some of the information that can be directly or indirectly inferred from some of the more common geophysical probes include: Formation Lithology (sand, shale, limestone, etc) Location of Producing Zones, Shape of the Borehole Water Quality within the Formation Porosity Temperature The geophysical logs commonly run in water wells are similar in every respect to those run in oil and gas wells. In 1927 what would become the widest application of electrical surveying was attempted, the electric
