Offshore safety watchdog revokes COSL rig order

  • Exploration & Production

The Petroleum Safety Authority Norway (PSA) changes the investigation report and its conclusion which stated that the structural design and dimensioning of COSLInnovator were not in accordance with the regulations at the time of the accident on December 30, 2015 in which one person died.

At the time of the incident, COSL Drilling’s 2011-built COSLInnovator semi-sub was working for the Norwegian oil company Statoil on the Troll field in the North Sea.

COSL Drilling said on Friday that the safety authority now confirms that there were no breaches of the construction regulations at the time of the accident. The safety authority said the decision has been made on the basis of new information in the case.

According to the PSA, 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.

Order withdrawn

The PSA informed COSL Drilling Europe on June 30, 2016 that the order issued after the investigation of the tragic accident on COSLInnovator has been withdrawn. In the order given on May 23, 2016, the PSA claimed that the rig, at the time of the incident, was not built in accordance with the regulations. COSL Drilling Europe was ordered to verify, through appropriate calculations or model tests, that the COSLInnovator, and its sister rigs COSLPromoter and COSLPioneer, comply with the construction regulations.

In their last statement to COSL Drilling Europe, the PSA refers to dialogue with the Norwegian Maritime Authority as well as new information, and concludes that the rig’s structural design and dimensioning at the time of the incident were and are in accordance with the construction regulations, COSL stated.

Namely, the PSA said it 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.

“Our focus the entire time has been to understand and learn the most out of this tragic incident that has affected the entire industry. Our responsibility is to ensure safe workplaces. Therefore, it was difficult to comprehend the initial conclusion of the PSA stating that regulatory breaches related to the structural design and dimensioning of the rig probably had significance for the extent of damage. Although this does not change anything regarding the tragic outcome of the accident, it is a considerable relief to us all that the PSA changed their conclusion,” says Jørgen Arnesen, CEO of COSL Drilling Europe.

“This is reassuring and there is every reason to give credit for the critical approach our regulators have had to their own conclusions in this matter,” Arnesen said.

In addition to the PSA revoking the issued order, the wordings of the investigation report have been adjusted in line with their new understanding. The revised report was sent to all affected parties on Wednesday July 6, COSL added.

“The PSA refers to the evaluation of new information when they on their own initiative reverse the order. This is reassuring and there is every reason to give credit for the critical approach our regulators have had to their own conclusions in this matter,” Arnesen comments.

After the incident, COSL Drilling Europe has carried out modifications on the drilling rigs. The company claimed that extensive model tests have also been carried out at Marintek in Trondheim, to verify these modifications and calculate the size of the horizontal forces that can occur from waves in the design area for the rigs.

The model tests were completed last week and large amounts of data will be analyzed over the coming weeks, said COSL. In this regard, COSL, concluded, PSA’s revocation of the issued order will have no practical consequences for the measures COSL Drilling Europe have put in place after the incident.

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