Joint
18 July 2017Kelly bushing (KB)
18 July 2017Kelly
The heavy steel member, three-, four-, six-, or eight- sided, suspended from the swivel through the rotary table and connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns. It has a bored passageway that permits fluid to be circulated into the drill stem and up the annulus, or vice versa.
See drill stem, rotary table, and swivel.