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Electric Logging (ELOG)

The Elog is the classic water-well combination probe combining shallow, medium and deep penetrating resistivity measurements with self-potential (SP).

Principle of Measurement:

A low-frequency bi-directional electric current from a source electrode on the probe returns through the formation to the cable armour above an insulated bridle. Potentials due to this current flow are measured on various sense electrodes on the probe with respect to a voltage reference ‘fish’ normally located at the surface. These measurements are converted to apparent formation resistivities within the probe and digitally transmitted to the surface.


  • Digital down-hole measurement avoids errors due to cable effects
  • Constant-power down-hole current source give 4 decades of measurement without manual range switching


  • 16” Normal resistivity
  • 64” Normal resistivity
  • Single-point resistance
  • Self-potential SP
  • Natural-gamma
  • Temperature
  • Optional 8” and 32” Normal resistivity



  • Determination of water quality
  • Indication of permeable zones and porosity
  • Minerals/Engineering
  • Bed-boundary positions
  • Strata correlation between boreholes


Diameter: 44mm
Length: 2.70m or 2.94m (with 8” and 32” option)
Weight: 9.8kg
Temperature: 0-70⁰C (extended ranges available)
Max. pressure: 20MPa
Resistivity range: 1 to 2,000 ohm-m

Operating Conditions

  • Borehole type: open-hole, water-filled

Sales Information

I002072 Electric logging probe with natural gamma and temperature
I002111 – including 8” and 32” normal resistivity

Download Electric Logging (ELOG) sheet


...Practical Innovation with Global Service & Support...

Robertson Geologging Ltd., 2017

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