Alert 99 – 32 Top Drive Swivel Stem Parted
WHAT HAPPENED:
The rig experienced a drilling break. While picking up the drill string to check for flow, the connection between the swivel stem and the double-pin sub parted. The string dropped about 20 feet (6 m) to the bottom of the hole with another 30 feet (9 m) of compression. The top drive was connected to the torque tube, which kept it from falling over when it was dropped to near the floor. However, it allowed enough lateral movement to bend the drill pipe. There was no leakage to indicate a cracked swivel stem prior to the time it parted.