دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a device similar to a power swivel that is used in place of the rotary table to turn the drill stem. It also includes power tongs. Modem top drives combine the elevator, the tongs, the swivel, and the hook. Even though the rotary table assembly is not used to rotate the drill stem and bit, the topdrive system retains it to provide a place to set the slips to suspend the drill stem when drilling stops.

a rig with the pipe rotation mechanism in the traveling block section. Usually does not use a Kelly.