LATEROLOG 3, ALSO REFERRED TO AS A FOCUSED RESISTIVITY LOG, LL3, RLL3, OR GUARD TOOL
The Laterolog 3, like the Electric Log, is a galvanic resistivity device using three electrodes instead of two. The current flows from the “A” electrode located at the center of the tool, varying in density as a function of formation conductivity. A zero potential gradient is maintained with the other two electrodes. This array focuses the current into a disc approximately 4 inches thick.
Under standard conditions, where the medium is constant and homogenous, the tool can fully resolve beds as thin as 4 inches.
In freshwater formations of sedimentary material, the resistivity measured with Laterolog 3 is primarily a function of grain size, distribution, and sorting.
The Laterolog 3 is an excellent correlation log with the Gamma-Ray, Sonic Velocity, and other logs in water or mud-filled boreholes.
The 5-point calibration provides a dynamic range for various formation types with excellent bed resolution. The tool also has a gamma-ray sensor. The log comprises (2) separate measurements:
• RLL3 Laterolog 3 Resistivity
• GR Gamma Ray
The Laterolog 3 is generally run in conjunction with the Electric Log, where the data is presented side by side and overlaid for ease in correlating.
