STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

Drilling Bits and Downhole Tools 825
Stabilizer Design. There are four commonly used stabilizer designs.
Solid-vpe Stabilizers. (See Figure 4-180.) These stabilizers have no moving
or replaceable parts, and consist of mandrel and blades that can be one piece
alloy steel (integral blade stabilizer) or blades welded on the mandrel (weld-on
blade stabilizer). The blades can be straight, or spiral, and their working surface
is either hardfaced with tungsten carbide inserts or diamonds [57,58].
Repl8Ceable-BladeS Stabilizers. (See Figure 4-181 [58A].) These stabilizers can
maintain full gauge stabilization. Their blades can be changed at the rig with
hand tools; no machining or welding is required.
Sleeve-vpe Stabilizers. (See Figure 4-182.) These stabilizers have replaceable
sleeve that can be changed in the field. There are two types of sleeve-type
stabilizers: the rotating sleeve-type stabilizer (Figure 4-182A [58]) and the
nonrotating sleeve-type stabilizer (Figure 4-182B [59]). Rotating sleeve-type
stabilizers have no moving parts and work in the same way as solid-type
stabilizers. Nonrotating sleeve-type stabilizers have a nonrotating rubber sleeve
supported by the wall of the borehole. The rubber sleeve stiffens the drill collar
string in packed hole operations just like a bushing.
Reamers. (See Figure 4-183 [59].) Reamers are stabilizers with cutting elements
embedded in their fins, and are used to maintain hole gage and drill out doglegs
and keyseats in hard formations. Because of the cutting ability of the reamer,
the bit performs less work on maintaining hole gauge and more work on drilling
A 8
C
D
Integral Blade Weld-On Blade Big BearTM Near-Bit Diamond Near-Bit
Stabilizer. Hardfacing Stabilizer. Alloy steel Stabilizer. Granular Stabilizer
with tungsten carbide hardfacing. (Servco) tungsten carbide (Christensen)
compacts. (Servco)
hardfacing. (Servco)
Figure 4-1 80. Solid-type stabilizers. (Courtesy Smith lnternafional and Baken
Hughes INTEC?)