Carrier rig:A large, specially designed, self-propelled workover rig that a person drives directly to the well site.
Power from a carrier rig’s hoist engine or engines also propels the rig on the road.
While a carrier rig is primarily intended to perform workovers, it can also be used to drill relatively shallow wells.
A carrier rig may be a back-in type or a drive-in type.
See back-in unit, drive-in unit.