WellCAD Basics - Advanced Logic Technology

396 - APPENDIX A
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The following sketch shows the relationship between caliper and dip angle:
�z
Sine curve fitted to unrolled borehole wall
cal
��
�z �z
scan (left). A sketch of a borehole with intersecting structure and the relation between dip angle (�), caliper
(cal) and from sine curve derived �z is shown on the right.
�z
The dip angle � is linked to the caliper through: tan � � . Therefore you can
cal
either enter an estimated constant caliper value into the Fixed To edit box or you
use a caliper channel using the Using Log option. Whichever option you choose
the values must be in inches or millimeter as indicated by the Caliper Unit field.
When changing the caliper information you will be asked whether you want to
recalculate all dip angle values. If you choose Yes all dip data values will be changed.
If your selection is No, the data display changes according to the new caliper
settings. This might result in a mismatch between observed and picked structure.
To swap the references and count the azimuth angle from the right log column
border instead from the left, check the Reverse option.
If yo would like to enable the vertical grid display check the corresponding option.