Downhole fluid-tight flexible joint

摘要

A downhole tool comprises a joint, and a resilient member 65 which extends through the joint and provides a restoring force which tends to strengthen the joint. The joint may comprise a flex coupling 61 which allows limited articulation of the joint. First and second drill string sections 63, 64 may be interconnected by the joint, the resilient member 65 being fixed to interior surfaces of the first and second drill string sections 63, 64. A downhole tool may also comprise primary and secondary sleeves 46 that are supported relative to the mandrel 10 of the drill string. Rotational drive may be transferred from one of the sleeves to the other.