Borehole Deviation


The QL40-DEV measures the direction relative to magnetic north, inclination and trajectory of the borehole. Measurements are based on the “Applied Physics Systems” 544 orientation sensor containing both a 3-axis fluxgate magnetometer and a 3-axis accelerometer. Deviation parameters are calculated in real time and displayed as continuous logs during the measurement.

Deviation data can be processed further using the WellCAD software and deviation module. The WellCAD deviation module includes various 2D and 3D display options for deviation data from classical bull’s eye, projection and closure 2D views to 3D cubic and cylindrical displays.

The QL40-DEV is supplied as a middle 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, Scout and ALTlogger acquisition systems.


APS544-3 axis magnetometer and accelerometer

Temperature – Pressure

0-70°C (32-158°F)
200 bar (2900 psi)

Diameter – Length

40 mm (1.6”) – 0.7 m (28”)


3.4 kg


Angular values of azimuth, tilt and relative bearing

Calibrated values of each accelerometer and magnetometer components


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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