Although our industry has not done the best job of describing these systems clearly, the differences are rather simple.
Power swivel means a drilling machine that includes 4 functions:
- Hydraulic powered pipe rotation,
- The ability to safely hang the rotating pipe load,
- A sealing arrangement which allows pumping high pressure drilling fluid from the mud pump through the rotating main shaft or stem.
- Torque is reacted with cable(s) and torque arms.
Top drive means an automated drilling and pipe handling system which includes the functions of a power swivel. The additional functions provided by the top drive include:
- An elevator and links which may be hydraulically manipulated by the driller to pick up pipe from the mouse hole, the V-door, or the vertical racked position in the derrick,
- The time-saving ability to trip pipe without removing the power swivel,
- The time-saving ability to drill down with doubles or triples,
- The ability to make or break connections above the rig floor by remote control,
- Torque is reacted with a torque track.
