Suitable for oil wells, gas wells, coal mines or under high temperature conditions. The cables marked with Dry; They are a series of cables in which the typical water blocking the intermediate tubes (gelatin, water swelling tape or powder) is replaced with a solid. Principle: Utilizes Raman scattering to measure the temperature along the wellbore. Reinsch 1 1 GFZ German Research Centre for Geosciences 2 BAW Federal Waterways Engineering and. These monitoring systems help. Optical fiber logging cable is a type of cable used in oil and gas well logging applications. Logging cable is used to lower instruments into wellbores to take measurements of the subsurface.