Norway’s Petroleum Safety Authority (PSA) is retracting an order handed to COSL Drilling Europe in April regarding a fatal accident onboard the COSL Innovator on 30 December 2015, after discovering new information and finding that no deviations were found in the design of the rig.
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The COSL Innovator, image from COSL. |
Following discussions with COSL, the PSA, and the Norwegian Maritime Authority (NMA) decided that grounds are present for withdrawing the decision to make the order.
“This new information relates to the application of the regulations, and makes it clear that the regulations have been too vague with regard to the applicable calculation methodology for horizontal wave forces on mobile units,” the PSA said. “The PSA has amended its investigation report to reflect the fact that conditions related to the air gap and horizontal wave slamming did not represent breaches of the regulations at the time of the incident.”
In April, the PSA had originally said that the COSL Innovator did not have an air gap of 1.5m between the underside of the lowest deck and the highest wave crest while operating at Statoil’s Troll field offshore Norway. The agency had ruled that at the time of the incident, the unit’s superstructure was not dimensioned to resist horizontal wave loads.
COSL teamed up with Statoil and Aker Solutions earlier this year to conduct its own internal investigation, and strongly disagreed with the PSA’s initial ruling.
“We have always been keen to understand and learn the most by this tragic event, which has affected the entire industry. Our responsibility is to ensure safe workplaces. Therefore, it was difficult to put up with PSA's initial conclusion that the breach of regulations related to the rig design and dimensioning probably had significance for the damage. Although this now does not change anything for the accident tragic outcome, there is a considerable relief to us all that the PSA change its decision,” said Jorgen Arnesen, CEO of COSL Drilling Europe.
Following the fatal incident that killed one person and injured two others, COSL made repairs to its drilling rigs, and carried out extensive model tests for Marintek in Trondheim to verify reinforcements and calculate the size of the horizontal forces that can arise from the waves in the area of design for the rigs. According to the company, model tests were completed last week and large amounts of data will now be analyzed over the coming weeks.
The PSA is now collaborating with the NMA and DNV GL to clarify their requirements in order to ensure that new lessons, which have been learned from the December incident, are taken into account. The requirements include better guidelines for calculating the air gap and horizontal wave slamming on semisubmersible facilities.
Read more:
PSA: COSL rig not built for big waves
1 dead, 2 injured in Troll accident
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