HIGH EFFICIENCY DRILLING AND TRIPPING SYSTEM

摘要

Apparatus for use in subsurface drilling permits coupling and uncoupling of drill string sections while continuously moving the drill string. Tripping times can be reduced while maintaining low speeds of the drill string. In one embodiment coupling units operable to make or break couplings between drill string sections are arranged to circulate around a closed path. Each of the coupling units includes an elevator. Drill string sections may be passed off to a pipe handling system on a back side of the apparatus.