Which combination can help correct a crooked hole when using air rotary drilling?

• A. Using stabilizers to guide the bit and adjusting the drilling angle
• B. Increasing weight on the bit and decreasing air pressure
• C. Using stabilizers, reducing weight on the bit, and adjusting the drilling angle
• D. Switching to a larger drill string

Answer: (C)

When you need to correct a crooked hole in air rotary drilling, focus on controlling how the bit sits and moves in the hole, then steer from there. Stabilizers help keep the bit centered and aligned with the hole axis, reducing lateral wander and guiding the bit along the intended path. Reducing weight on the bit lessens the downward force that can push the bit toward one wall, which helps prevent the hole from bending away from a straight line. Adjusting the drilling angle gives you direct control to steer the bit back toward the desired trajectory by altering the contact geometry with the borehole wall. Together, these steps address both the alignment and the steering needed to straighten a crooked hole. Increasing weight while lowering air pressure can worsen deflection, and switching to a larger drill string doesn’t directly provide the steering control needed.