Norway’s offshore safety body, the Petroleum Safety Authority (PSA), has completed an investigation into an incident involving dropped objects on the Maersk Invincible drilling rig.
The incident occurred in the drilling module on November 11, 2018, when two tubular stands detached from the fingerboard and fell across the drill floor.
At the time, the jack-up rig was working for Aker BP on the Valhall field in the Norwegian North Sea.
Namely, the upper part of these tubular stands fell across to the opposite side of the derrick. Their lower section slid and hit the windshield and parts of the structure by the gangway on the drill floor.
According to the safety watchdog, each stand was 38 meters long and weighed about 1,300 kilograms.
The PSA’s investigation, which started several days after the incident , shows that the direct cause of the incident was the failure of the locking mechanism in the latches on the fingerboard to operate as intended. The safety body added that a strong wind was also blowing in the area at the time.
The PSA said on Thursday that the incident caused no injury to personnel even though people were present in the area around the drill floor. The incident caused minor material damage.
“When the drilling crew understood that the stands were in motion, however, it was decided to erect cordons to prevent access to the drill floor,” the safety body added.
The PSA’s investigation identified three breaches of the regulations regarding inadequate risk assessment and decision basis, inadequate experience transfer within the company, and inadequate locking mechanism on the fingerboard.
Maersk Drilling Norge, which operates Maersk Invincible, was told to explain to the PSA how it intends to deal with the non-conformities by April 8, 2019.
As for the rig, the Maersk Invincible is an XL Enhanced ultra-harsh environment jack-up rig. It was delivered by Daewoo Shipbuilding and Marine Engineering (DSME) in South Korea in January 2017 . The rig arrived in Stavanger, Norway, in late March 2017 .
Aker BP received consent from the PSA to use the Maersk Invincible rig for production drilling , well operations, and as a flotel on the Valhall Flank North and Valhall Flank South fields back in August 2018.