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Dual Induction

The dual induction probe provides conductivity logs with deep and medium depths of investigation. The tool uses an ‘array’ technique where multiple sets of in-phase and out-of- phase receiver responses are processed and summed to emulate the vertical and radial responses of classic 6FF40 ILD and ILM logs.

The tool may be combined with other measurements and is always run at the base of the stack. The probe includes a fast-response platinum resistance thermometer for measurement of external borehole temperature.

Principle of measurement:

An oscillating high-frequency magnetic field created by a transmitter coil within the probe induces an alternating electrical current within the surrounding conductive formation. This current, in turn, induces voltages within multiple receiver coils in the probe proportional to formation conductivity. The transmitter-receiver spacings determine the depth of investigation of the measurements.


  • Multiple coil ‘array’ measurement using computer processing to synthesize tool responses
  • Internal temperature compensation for low drift
  • Oil-filled and pressure-balanced mandrel
  • Fully digital telemetry combines with density, neutron and other logging probes
  • High-resolution measurement.
  • Maximum data sampling rate is 1cm (0.4”)
  • Includes external temperature measurement


  • Deep conductivity (ILD)
  • Medium conductivity (ILM)
  • Raw conductivity channels
  • Temperature and differential temperature


  • Hydrocarbon saturation
  • Porosity
  • Lithology (in conjunction with other logs)
  • Correlation between wells


Diameter: 63mm (2.5”)
Length: 4.01m (159”)
Weight: 31kg (68lb)
Max. temperature: 125°C
Max. pressure: 86MPa (12,500psi)
Resistivity range: 0 to 200ohm-m
(Qualitative indication up to 2000ohm-m)
Depth of investigation: ILD 60”
ILM 30”

Operating Conditions

Borehole type: 4” to 12” mud or air-filled open hole

Sales Information

I003947 Dual induction probe with temperature
I004133 Calibration loop
I004134 Fin stand-off (set of two)

Download Dual Induction sheet


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

Robertson Geologging Ltd., 2017

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