WellCAD Basics - Advanced Logic Technology

148 - BOOK 1 - WELLCAD BASICS
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Magnetometers:
You can select the input channels for the computation from the corresponding drop
down lists. WellCAD assumes that the magnetometer data is calibrated in micro
Tesla units. Ensure the selected components correspond to the required orientation
of the reference axis system. A sketch of the required axis orientation is given in the
Axis System field. It is a right-handed system with the z-axis pointing out of the
borehole (up).
If the sign of the incoming data must be reversed click the little button to the right
of the drop down list to toggle the sign.
Inclinometer / Accelerometer:
Choose whether the input channels contain Accelerometer or Inclinometer data.
Next select the input channels and ensure the components correspond to the
reference axis orientation. WellCAD assumes that the inclinometer data is calibrated
in degrees.
Marker position:
The Marker Position is the angle between the first point of recording and the y-axis.
If we think about an acoustic televiewer the marker position would be the angle
between the position on a circle where first measurement was made and the y-axis.
The Marker Position value is only used for the calculation of the RBR values.
Tool X
First Trace
MP – Marker Position
Tool Y
Illustration of tool axis system given by the orientation device and marker position
For ALT’s FAC, ABI and OBI tools the marker position can be retrieved from the
tool’s *.TOL file.