STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

920 Drilling and Well Completions
328.29'
/
Top view of
Plane Normal to
Oz in 0
Trace of Borehole Axis
+
Down
b)
X
Figure 4-233. Representation of the three main vectors: (a) solid geometry
view; (b) projection on plan normal to 0,.
Note: Another way, probably less ambiguous, to compute the azimuth is to make a rotation of
coordinates around Oz to bring Ox in the vertical plane and Oy in the horizontal plane. Then,
make another rotation around Oy to bring Oz vertical and Ox in the horizontal plane. The azimuth
is the clockwise angle between the new OH: and Ox.
Example 4: Steering Tool Measurements-Trajectory
Forecast
An interesting problem that can be solved with the steering tool or the MWD
measurements is the trajectory forecast when drilling ahead with a given bent
sub (constant angle), and a given tool-face angle.
1. After drilling the mud motor length with a given tool face angle and a
given bent sub angle, what is the borehole deviation and orientation likely
to be at the mud motor depth?