Once the hole is made and cuttings are cleared from the bit face, these cuttings must be completely removed from the hole and the walls of the hole stabilized.
Drilling cannot continue until the hole is clean and open.
The following table summarises hole stabilisation methods for diferent drilling methods. Holes may be
- using casing (C)
- hydrostatic pressure (H)
- a wallbuilding process (W) or
- using the drill rods (R) (when the rods are close to hole size).
Hole stabilisation methods