Alert 12 – 28 Driller Inattention Results in Dropped Blocks
While tripping in the hole, the driller was washing and reaming due to a tight hole. After raising a full stand past the derrick board, the driller started to lower the stand back down when they hit a bridge causing the blocks to lay over the top drive which allowed the drill line to acquire slack above the blocks. As the blocks were falling towards the V-door the driller clutched the draw works and at the same time the bit broke through the bridge allowing the blocks and top drive to free fall and hit the end of the slack drill line. The sudden increase of weight parted the drill line 228 feet (69 meters) from the drum of the draw works. The blocks, top drive, and the drilling line fell to the rig floor.