| 摘要 |
A downhole tractor includes a control means that displaces at least three expanding drive bows 71, 72. The drive bows 71, 72 expand with respect to a tractor housing in order to engage a well bore or liner. Once engaged the drive bows 71, 72 enable the tractor to contact the well bore or liner and move with respect thereto. The tractor may be hydraulically operated. |
