Positioning deflection wedges

摘要

A deflection wedge is positioned in a long horizontal drill hole by securing it with a shear pin to an extension on a drill string. The extension is turned independently of the drill string to enable a droparm mechanism to actuate a trigger which stops rotation at a predetermined orientation. Rotation is effected by means of a piston-operated rifle bar mechanism. The piston is actuated by passing drilling fluid down the drill string. The trigger causes a valve to be closed to lock the piston hydraulically in position and thus prevent further rotation. The wedge is now secured by axial pressure on the drill string.