| 摘要 |
An under-reaming tool comprises a body and a plurality of extendable cutters mounted on the body. The under-reaming tool is configured to be cycled between a first configuration in which the cutters are retracted and a second configuration in which the cutters are movable between retracted and extended positions. The under-reaming tool is configured to prevent extension of the cutters by an external fluid in the first and/or second configuration/s. |
