IPC Definitions - January 01, 2012
E21B 47/02 - Definition
This group covers:
Processes or apparatus for finding either the degree of slant of the borehole or well with respect to the vertical or the angle between the path of the borehole or well and the line to the magnetic north.
Attention is drawn to the following places, which may be of interest for search:
Clinometers or direction meters in general | G01C |