U.S. regulator says lack of training played a part in fatality aboard drillship in Gulf of Mexico
Following the publishing of an investigation report, which looked into a fatality aboard a drillship during well operations in the Gulf of Mexico, the U.S. Bureau of Safety and Environmental Enforcement (BSEE) has outlined that the lack of training with a hydraulic torque wrench (HTW) contributed to the fatality.
In a safety alert published last week, BSEE explained that a crewmember was lifted into the air after being struck by a hydraulic torque wrench, hitting a riser clamp approximately six feet above the elevated work deck before falling to the rig floor. This occurred on 23 August 2020 during the unlatching of the lower marine riser package from the blowout preventer in preparation for ship relocation. The crewmember was given first aid and transported to the Pacific Khamsin drillship’s hospital, where he was later pronounced deceased.
At the time of the incident, the Pacific Khamsin drillship was owned by Pacific Drilling. However, following Pacific’s merger with Noble Corporation in March 2021, the drillship is now owned by Noble.
The 2013-built Pacific Khamsin is a 748-foot drillship designed by Samsung Heavy Industries as a 12,000 double hull with a dynamic positioning system that can operate in water depths up to 12,000 feet and drill to a maximum depth of 40,000 feet. The rig contains permanent living accommodations to sustain 200 personnel.
The main power for the drillship is supplied by six 8,000-kilowatt engines running at 720 revolutions per minute, each driving a 7,760-kilowatt generator. This power can support all functions aboard the drillship, including the shut-in of two NOV-Shaffer, 18.75-inch, 15,000 psi, six Ram blowout preventers (BOPs) with two 18.75-inch, 10,000 psi annular, all run through an 84-foot by 41-foot moonpool.
During the incident, the drillship was under a contract with TEPUSA in the North Platte region to spud new exploration wells after it arrived at GB Block 1003 in May 2020 to land and test its subsea BOPs in preparation for drilling operations.
According to BSEE, the incident investigation found that the rig crew was using a hydraulic torque wrench to extract the bolts from a telescopic riser joint (TJ) flange.
During the operation, the HTW T socket became stuck between the bolt head and the tapered edge of the TJ. After failing to manually dislodge the HTW using physical exertion, the rig crew utilised a hydraulic utility wrench to supply upward force and applied tension to free the tool.
After applying the upward force, the torque wrench became unstuck under tension and shot upwards leading to the crewmember being struck.
The U.S. regulator claims that contributing factors to this incident include a lack of recognising the stuck-HTW potential on the TJ bevelled edge, a lack of comprehensive understanding of the task risk assessments associated with the riser pull, failure to effectively communicate all learnings from the previous riser pulls, lack of formalised training for the utilisation of the HTW and HUW, and adverse designs of the HTW and the HUW.
On the other hand, BSEE highlights that contributing causes to the incident encompass the failure to initiate Stop Work Authority and discrepancies with the Drill Floor Observer roles and responsibilities.
Recommendations for operators and contractors
Bering this in mind, BSEE recommends that operators and contractors ensure the Job Safety Analysis captures the limitations of the HTW when in use; verify all employees understand the Job Safety Analysis and have been formally trained on operating both the HTW and HUW; emphasise the initiation of Stop Work Authority if an imminent danger is observed; and expand the Drill Floor Observer responsibilities to monitor all aspects of jobs occurring on the rig floor.
In addition, the U.S. regulator explains that operators and contractors should consider utilising an HTW with a compatible design that corresponds with the bevelled edge of the TJ; explore options for employing a load indicator, or a similar design mechanism onto the HUW package; and ensure pre-job reviews, promote the sharing of feedback from previous experiences.