After worker suffers ‘crushing injuries’ during work on jack-up rig, probe reveals nonconformities

Norwegian offshore safety regulator has completed an investigation into an incident involving an injury during work on a drag chain on a jack-up rig, working in the North Sea at one of the fields on the Norwegian continental shelf (NCS), and is awaiting a response from Odfjell Technology regarding the way the identified nonconformities will be handled.

West Linus rig; Source: Seadrill

The Petroleum Safety Authority Norway (PSA) confirmed recently that it had completed its investigation of an incident on the West Linus jack-up rig, which occurred on 10 November 2022 while the rig was carrying out its assignment on the Tommeliten field in the North Sea, where ConocoPhillips is the operator. 

The incident occurred during repairs to the port drag chain on the West Linus jack-up rig, which is operated by Odfjell Technology. The regulator explains that a drag chain is a linked cable/pipe tray carrying power cables and hoses to supply water, drilling mud and air to the cantilevered drilling rig when the latter is skidded between various well slots.

According to the PSA, the port drag chain on the West Linus rig, measuring 115 centimetres wide, comprises two cable trays, one atop the other. One of its outer plates was damaged (bent), and a two-member team comprising the injured person and its assistant were to look at this and consider what to do.

The injured person had undone the nuts on a damaged side plate in one of the drag chain links and was lying between the upper and lower drag chain when the upper section collapsed and parts of the chain dropped and compressed his arm and head. The weight of the collapsed structure was considerable, with the load cell on the offshore crane showing about two tonnes, when the police came to secure the injury site for their investigation.

The regulator highlighted that the injured person’s head and left arm were compressed and crushing injuries meant his arm had to be amputated between shoulder and elbow. The worker’s assistant suffered no physical injury during the incident and the drilling operation was halted for 48 hours from the time of the injury.

Based on the PSA’s statement, the most important direct cause was the collapse of the drag chain over the injured person, which occurred after he had undone several nuts on a damaged side plate for workshop repair.

“The job was not registered, planned or risk-assessed in accordance with the requirements in the company’s governing systems. Underlying causes were a lack of control and management of technical condition, lack of job control, deficiencies in governing documents and procedures, and inadequate handover routines and clarification of roles and responsibilities,” underlined the regulator.

West Linus rig; Source: Seadrill
West Linus rig; Source: Seadrill

While the incident occurred the day after a swing shift from night to day work, it is unclear whether this might have affected the assessment of the risk posed by the repair work. The offshore safety watchdog highlights that in minimally different circumstances, this incident could have had a fatal outcome for both the injured person and his assistant.

While conducting its investigation, the PSA identified seven breaches of the regulations. The nonconformities that the regulator found include registration and classification, procedures and work description for the drag chain, roles and responsibilities, decision basis and safety clearance, compliance with governing documents, noise, and information at shift and crew changes. In addition, the regulator has identified one improvement point related to mustering and POB.

With the PSA’s investigation completed, the regulator has asked Odfjell Technology to report how these nonconformities will be addressed by 23 March 2023 and to provide its assessment of the improvement point observed.

The 2014-built West Linus rig is employed on a long-term drilling contract with ConocoPhillips Skandinavia in the North Sea until the fourth quarter of 2028.

The rig is operated by Odfjell thanks to arrangements made in February 2022 with SFL. This enabled the offshore drilling contractor to provide management services for this jack-up drilling rig and replace Seadrill as the rig manager as soon as regulatory approvals were received from Norwegian authorities.