Alert 98 – 26 More on Casing Safety
WHAT HAPPENED:
After running all 9-5/8″ casing, the 10-3/4″ 500-ton elevator was rigged up with the operating lever facing the opposite direction from the stabbing board. A 9-5/8″/10-3/4″ crossover joint was made up, and the 500-ton elevator was lowered below the coupling. Because the length of the crossover joint was only 5.2 meters (17 feet), it was impossible for the stabber to reach the lever. The stabber was told to climb on the elevator, but it was necessary to raise the blocks for him to do this. It was decided then to close the elevator on the coupling with the intention of lowering the blocks afterwards so the slip would engage on the pipe body. But the blocks were raised too far, so that only the bottom three inches of the inserts were covering the top three inches of the coupling. In this position, the stabber closed the elevator. While the stabber was climbing back to the stabbing board the blocks were lowered to reach the pipe body. During this action, two cylinders of the elevator broke off. Rig floor personnel were under the impression that the inserts were set onto the pipe body due to the noise made. The string then was raised and the Flush Mounted Spider (FMS) was opened. The elevators were lifted a few additional meters to allow changing the FMS easier. At that point, the elevator lost its grip, dropping the complete string into the hole.