COILED TUBING DRILLING SYSTEM

摘要

A drilling rig for drilling an underground borehole (5) into a seam (4) uses coiled metal tubing (8) fed by a tractor unit (11) from a drum (7) to provide a thrust force to a drilling head. The drilling head has a bent-sub assembly giving an angle of deviation which is controlled by rotating the coiled metal tubing in the borehole by way of rotation of the drum (7) in the frame (12) about the axis of the tube in the borehole (5).