Page 191 - Drilling Technology in Nontechnical Language

182 Drilling Technology in Nontechnical Language Second Edition

Fig. 8–5. Steerable motor assembly

While drilling, the motor can be orientated in a desired direction,
and the bit drills a curved hole. This can be used to turn the hole, drop
angle, build angle, or some combination of build/drop and turn. The whole
drillstring can also be rotated so that the bit will drill straight ahead. This
is why it is called a steerable motor—it has the capability to really be
steered to cut the required path, which can be quite complex.
Steerable motors are very commonly used for initially kicking off the
well from vertical and for continuing to drill and control the well path
after the kickoff. As the well inclination increases above about 60°, it starts

to get difficult to make such an assembly slide (drill without rotating the

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