| 摘要 |
A downhole apparatus 10 that is selectively reconfigurable between a first configuration and a second configuration includes an actuator 24 for controlling the reconfiguration between the first and second configurations. The actuator 24 comprises a rotationally-activatable device 26, the rotationally-activatable device 26 being substantially unaffected by gravitational orientation such that the apparatus 10 is suitable for use in at least one of a deviated bore, and a horizontal bore. The apparatus may be an underreamer or reamer and reconfiguration may occur according to a rotational parameter or a fluid parameter. The rotationally activated device 26 may include movable masses 30a-c to offset the action of gravity. |
