| 摘要 |
A wireline tractor includes a displacement mechanism and at least one driving wheel positioned on the displacement mechanism so that the driving wheel is held in a biasing manner against a well wall. The displacement mechanism is rotatable or movable between a first position at which the driving wheel bears against the well wall on one side of the wireline tractor, and a second position at which the driving wheel bears against the well wall on the opposite side of the wireline tractor. |
