Page 89 - Air and gas Drilling Field Guide 3rd Edition

80 CHAPTER 4 Downhole Equipment

Sleeve Rubber
Type Sleeve
Stabilizer Stabilizer

FIGURE 4-18. Nonrotating blade stabilizers (courtesy of Smith International).

Figure 4-19 shows a three-point rolling cutter reamer. These reamers have the

roller cutters 120 apart on the circumference. The rolling cutter reamer is a spe-
cial type of stabilizer tool that provides “blades,” which are cylindrical roller cutter
elements that can crush and remove rock from the borehole wall as the drill bit is
advanced. Often the reamer is placed just above the drill bit (replacing the near bit
stabilizer, see Figure 4-16). Reamers are also available in a four-point rolling cutter
reamer. These reamers have the rolling cutters 90 apart on the circumference.

Such rolling cutter reamers are used when drilling in abrasive, hard rock for-
mations. The gauge of the rolling cutter reamers can be adjusted by replacing
the rolling cutter elements on the stabilizer body with different outside diameter
elements. Also, damaged rolling cutters can be replaced. These replacements can
be accomplished at the drilling rig location. When drilling abrasive, hard rock for-
mations, the gauge of the rolling cutter reamers is usually adjusted to be slightly