The QL40-DEV Borehole Deviation probe 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 tool is stackable within the Quick Link (QL) product line or it can be run as a standalone tool.


  • Borehole True Vertical Depth
  • Borehole trajectory based on direction, inclination and drift measurement
  • True bed thickness
  • Location of magnetic beds or steel piles near borehole (z-component of magnetometer)

Operating Conditions

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

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

[X] Non-Magnetic Centralizers
[_] Not Necessary

Features & Benefits

  • In comparison with tools from competitors, the QL40-DEV is capable of recording exceedingly accurate Inclination and Azimuth data.
  • Operates on any standard wireline (Mono, 4, 7 conductor, or Coax)
  • Slim, 40 mm diameter. One-person operation.
  • Can be combined with other logging tools of the QL product line or operated as a standalone tool.
  • Measurements are accurate and consistent.

Specifications – Metric/English

Specification Metric Imperial
Diameter 40 mm 1.57 in.
Length 0.715 m 28″
Weight 3.4 kg 7.5 lbs.
Max. Temp. 70ºC 158ºF
Max. Pressure 200 bar 2900 psi


Sensor: APS 544
Orientation: 3-Axis Magnetometer, 3-Axis Accelerometer
Inclination Range: 0-180º
Inclination Accuracy: ± 0.5º
Azimuth Range: 0-360º
Azimuth Accuracy: ± 1.2º

QL Stack Possibilities

  • QL40DEV + QL40GR (Gamma): Deviation and Gamma Correlation
  • QL40DEV + QL40CAL (Caliper): Borehole Volume and Orientation
  • QL40DEV + QL40SGR (Spectral Gamma): Clay Typing, Detailed Lithology, Ore Body Identification

WellCAD Deviation Module

QL40-DEV WellCAD Deviation Module

QL40-DEV WellCAD Deviation Module

WellCAD® Software is an advanced log processing and visualization software recommended for use with all Mount Sopris logging probes. The WellCAD Deviation Module, used in conjunction with the QL40-DEV Deviation probe provides:

  • A variety of 2D and 3D display options including 2D Classical Bull’s Eye, Projection, and Closure and 3D Cubic and Cylindrical.
  • Multiple well paths and target layers can be displayed.
  • Processing techniques: Northing, Easting, Total Vertical Distance (TVD), Closure Distance, Closure Angle, and Dog Leg Severity (DLS).
  • Correction for Magnetic Declination and shows Estimation of Uncertainty.

For more information, please refer to the WellCAD Deviation Module Data Sheet.


Data Sheet
User Guide

Print Friendly, PDF & Email