Stabilisers and Hole Openers
Stabilisers that centre the string in the hole and hole openers that enlarge a pilot hole to final diameter. Both manage straightness and rig capacity limits.
Features
- Stabilisers reduce bit wobble, which is what extends roller-cone bearing life and holds hole straightness.
- Stabiliser outside diameter has to be slightly under hole diameter; too tight and the string sticks, too loose and it does nothing.
- Hole openers cut a larger diameter behind a pilot bit, so a rig short on pull-down can still make a large hole.
- Cutter arrangement on a hole opener is chosen for the formation in the same way as a roller-cone bit.
- Wear pads and hardfacing on stabilisers are refurbishable, which is cheaper than replacement.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Tool type | stabiliser / hole opener / reamer | They solve different problems and are not interchangeable. |