Alert 11 – 19 Drilling Line Slips Out of Retainer Clamp Results in Rig Downtime


While tripping in the hole, the driller was hoisting the top drive and empty elevators to latch a stand when a loud “slapping” noise was heard from the drawworks and severe vibration was noted in the brake handle. The block’s travel was stopped, and a large “bird’s nest” was seen on the drawworks drum. The rig floor was cleared of all personnel and a risk assessment was performed. It was decided to install a short hang-off line in the mast to hang the traveling block in its then-current position. When the drilling line was inspected, it was discovered that the drilling line had pulled out of the drilling line clamp in the drawworks. The loose end of the drilling line striking the drawworks guards was determined to have been the cause of the “slapping” noise heard at the time of the incident. The damaged drilling line was removed from the drum, and a new line clamp was installed including new bolts, nuts and lock washers. The line was spooled back onto the drawworks and the blocks were lowered and re-hung at the normal height for slipping and cutting drilling line. A thorough inspection of the drawworks, top drive, mast and drilling line were then performed. Minor damage was repaired on grease lines and crown-saver air lines. The crown-saver was tested and the rig resumed normal operations. This event resulted in 13 hours of rig repair time; no injuries were reported.

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