The friction-reducing drill pipe component in the form of a sub (10) is adapted to form part of a drill string. The sub (10) comprises a tubular mandrel (12) having first and second ends for connection to adjacent components of the drill string. A sleeve (18) is mounted on the mandrel (12), and first and second stops on the mandrel (16, 20) restrain the sleeve (18) against axial movement relative to the mandrel (12). One of the stops (20) is removable or retractable to permit the sleeve (18) to be removed over the first end of the mandrel.
申请公布号
WO9708423(A1)
申请公布日期
1997.03.06
申请号
WO1996GB02123
申请日期
1996.08.30
申请人
DRILLTECH SERVICES (NORTH SEA) LIMITED;APPLETON, ROBERT, PATRICK;RASTEGAR, GHOLAM, HOSSEIN