Page 88 - Air and gas Drilling Field Guide 3rd Edition

4.3 Bottom Hole Assembly 79

Welded
Blade
Stabilizer
Integral
Blade
Stabilizer

Big Bear
Stabilizer

FIGURE 4-17. Rotating blade stabilizers (courtesy of Smith International Incorporated).

blades become worn or damaged, they can be returned to the machine shop for
repairs.
Nonrotating blade stabilizers can be repaired at the drilling rig location.
Worn sleeves can be removed and new ones placed on the stabilizer body. This
is an important advantage over the rotating stabilizer. The nonrotating stabilizer
is most effective in abrasive, hard rock formations, as the sleeve is stationary
and acts like a drilling bushing. This action decreases wear on the metal
sleeve blades.
Stabilizers are used extensively to improve thestraightholedrill capability of
a BHA for both mud drilling operations and air drilling operations. However,
care must be exercised in using stabilizers in air drilling operations. The wear
rate on stabilizer blades in air drilling operations will be greater than in a mud
drilling operation (assuming similar geologic conditions).