Magnetic Ground

Magnetic borehole survey tools uses magnetometers to measure the direction of the tool axis with reference to magnetic north. For correct results it is necessary that magnetic north corresponds with the magnetic north pole. In areas where there are magnetic minerals or iron based material the magnetic field will be affected, and its direction may no longer point towards magnetic north.

The accelerometers are used to detect inclination and gravity tool face (rotation) with reference to the gravity field vector. The main factor influencing the gravity field vector is movement, and the survey tools should not be expected to provide accurate inclination data in situations where it is subject to acceleration (movement, vibration, etc).