Fluid Temperature and Conductivity


The QL40-FTC sub provides borehole temperature and fluid conductivity measurements. In comparison with tools from competitors, the QL40-FTC is capable of recording a wide range of conductivity from fresh to highly saturated water. 

The borehole fluid temperature measurement is helpful to detect anomalies caused by events such as fluid flow into the borehole. It is also used to normalize the conductivity measurement which is temperature dependent and so allowing comparisons between boreholes.

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.

The QL40-FTC is supplied as a bottom sub. It can be combined with other logging tools of the QL (Quick Link) product line or can be operated as a standalone tool. It is compatible with Matrix, BBOX and ALTlogger acquisition systems.

Temperature – Pressure

0-70°C (32-158°F)
200 bar (2900 psi)

Diameter – Length

40mm (1.6’’) – 0.8m (31.5’’) bottom sub
50mm (2’’) – 1.01m (39.8’’) in line sub


3.3kg (14lbs) – 6.6kg (28lbs)


Fluid temperature in °C

Fluid conductivity in µS/cm or mS/cm

Compensated conductivity at 25°C in µS/cm or mS/cm


Manufactured by Geotomographie GmbH

Technical Details

Generated wave types: SV
Signal frequencies: Up to 500 Hz (depending on geology and borehole distance)
Operational depth: Up to 100 m
Source length: 1015 mm
Source weight: 6 kg
Cable weight per metre: 377 g
Borehole diameter: 75-100 mm (or larger if spacers are used)
Clamping system: Infatable bladder
Depth indicator: Cable marking every 2 m
Connector: To impulse generator IPG800 or IPG5000
Storage: On drum
Switch box: Switch between two vertical shot directions

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