Patent ID: 9194212
Filing Date: 2015-11-24
Classification: E21B

Abstract:
1. A downhole actuator for a downhole drill string in a borehole of an oil or gas well, the downhole actuator comprising: a housing; an obstructing member moveable between a first position and a second position; a retaining member moveable in the housing between a retaining position which retains the obstructing member in the first position; a release position which does not retain the obstructing member in the first position and/or allows or causes the obstructing member to move to the second position; wherein the retaining member is adapted to move in use, from one of the retaining position and release position to another of the retaining position and release position, at least in part, by centrifugal forces; and wherein an entire drill string is rotated in the borehole and the centrifugal forces are caused by the rotation of the drill string in the borehole.