The U.S. Bureau of Safety and Environmental Enforcement (BSEE) is responding to a significant equipment failure on board a Transocean ultra-deepwater semi-submersible drilling rig in the Gulf of Mexico, approximately 100 miles south of Fourchon, Louisiana.
The offshore oil and gas operator, Shell Offshore Inc., reported that on June 9 the traveling block on board the Deepwater Nautilus fell during well operations.
Shell is monitoring the well and there are no reports of injuries to personnel or pollution, according to the BSEE. The project is limited to drilling and no production was affected by the incident.
BSEE engineers and inspectors have been discussing the on-going response with Shell and will travel offshore to the rig to investigate as soon as weather allows.
The traveling block is a large, freely moving series of pulleys or sheaves used to support the top drive which rotates drill pipe. On larger drilling rigs such as the Deepwater Nautilus, traveling blocks are often capable of handling loads well in excess of 1 million pounds.
Built in 2000 for Transocean, the Deepwater Nautilus can drill to a maximum depth of 30,000 feet and is rated for water depths of up to 8,000 feet. The rig is similar in design to the Deepwater Horizon, which in 2010 exploded and sank in the Gulf of Mexico, killing 11 people and resulting in the worst offshore oil spill in U.S. history. On the Horizon, the traveling block alone weighed in at 80 tons.
BSEE says it is investigating the incident and will provide more information as it becomes available.
Here’s what specifically happened:
While pulling out of the hole using 6 5/8″ drillpipe, the slips were set.
Soft broke the stand, spun out with the top drive and picked up out of the box
A ‘Maintenance torque up timeout for internal brake release’ alarm noted by the driller and brakes set.
ETs were called and noted ‘666’ fault on drive #1 & #4. Drives were rebooted to clear the fault.
The blocks started to descend and driller engaged ‘Emergency Stop’ cable to engage caliper brakes. Blocks came to rest on the BX elevators and bent 6 5/8″ DP.
Drill line parted on the last wrap on drums and became entangled on #6 and #7 sheave.
The Deepwater Millennium is being mobilized to replace the Nautilus while repairs are made. The gearbox and shaft within the top drive sustained damage as well as the drill shack.
You can join the gCaptain Forum thread about this incident HERE.