QL40-FTC – Fluid Temperature + Conductivity

Posted by on Aug 27, 2014 in Fluid Properties, Probes, Products | Comments Off on QL40-FTC – Fluid Temperature + Conductivity

QL40-FTC – Fluid Temperature + Conductivity



The QL40-FTC probe provides borehole temperature and fluid conductivity measurements.  The standard temperature log, based on a thermister, is designed to provide a measure of the ambient geothermal gradient and is helpful to detect anomalies caused by events such as fluid flow into the borehole.

The borehole fluid conductivity is directly proportional to the concentration of dissolved minerals. It is generally used in hydrogeology to determine the concentration of dissolved ions in the aquifers and to locate the fluid flows occurring in the borehole, especially if some time has passed and the temperature features have dissipated. It is important to differentiate between fluid inflow anomalies and formation conductivity anomalies identified on the temperature logs.

The QL40-FTC can be combined with other logging tools of the QL (Quick Link) product line or can be operated as a standalone tool.


  • Fluid conductivity – salinity
  • Salt-water intrusion studies
  • Identification of fluid flow in open/cased hole
  • Localization of the water table
  • Localization of water intervals of different quality
  • Water-well monitoring
  • Geothermal gradient logging
  • Often used in the implementation of temperature compensation equations for other logs

Operating Conditions

Borehole Fluid
[X] Water
[X] Mud
[X] Dry

[X] Uncased
[X] PVC Borehole
[X] Steel

[_] Required
[X] Not Necessary

Features & Benefits

  • In comparison with tools from competitors, this fluid temperature and conductivity tool is capable of recording a wide range of conductivity from fresh to highly saturated water.
  • Easy to calibrate. Measurements are accurate and consistent.
  • Operates on any standard wireline (mono, 4 or 7 conductor, coax)
  • Slim, 40 mm diameter. One-person operation

Specifications – Metric/English

Diameter40 mm1.6″
Length0.78 m30.7″
Weight3.35 Kg7.2 lbs.
Max. Temp.80ºC176ºF
Max. Pressure200 bar2900 psi


Conductivity Sensor: Seven electrode mirrored Wenner array
Conductivity Range: 5 µS/cm to 50,000 µS/cm
Conductivity Accuracy: 1%

Temperature Sensor: Linear, fast-response semi-conductor
Temperature Range: -20 to 80ºC
Temperature Accuracy: < 1%
Temperature Resolution: 0.004ºC

QL Stack Possibilities

  • QL40FTC + QL40GR (Gamma): Water-well Monitoring, Contaminant Intrusion Studies
  • QL40FTC + QL40GR (Gamma) + QL40ELOG (Resistivity): Identification of Aquifers
  • QL40FTC + QL40GR (Gamma) + QL40ELOG (Resistivity) + QL40CAL (Caliper): Hydrogeologist’s Tool, Groundwater exploration, assessment, and well completion


Data Sheet
User Guide

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