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Norway's PSA Investigates Welding Problems on New Equinor FPSO

equinor fpso johan castberg
Rendering of the future Johan Castberg FPSO (Equinor)

By The Maritime Executive 09-02-2020 08:25:38

Norway's Petroleum Safety Authority is launching an investigation into the problems with the construction of the giant FPSO for Equinor's new Johan Castberg offshore development. 

"The PSA became aware on 25 June 2020 that Equinor had identified major challenges with the quality of welds in the hull of the Johan Castberg floating production storage and offloading (FPSO) unit. In addition, the authority became aware that errors had been found in the analysis program used for fatigue calculations," the agency wrote in an announcement Wednesday. "Corrective work means that the FPSO hull will be delayed . . . Furthermore, efforts to correct weld and fatigue-analysis errors create uncertainty about the structure’s integrity over the producing life of the field."

The PSA has appointed a team of experts to look into why the project team for Johan Castberg did not identify the analysis mistakes and faulty welds earlier in the process. It will aim to establish the decisionmaking timeline, assess the consequences of the weld issues for safety, analyze causal factors and find any potential regulatory breaches. 

According to environmental NGO Bellona, the problems with the Johan Castberg FPSO became known in October 2019 and the software fatigue analysis issues have been known since April. The software's designer says that the calculation errors are manageable and will not force a major rework of the project. "The issue is mainly seen on FPSOs with weather-vaning capabilities and may impact the estimated fatigue life of the vessel, which has no immediate consequence for its structural safety,” the firm wrote. 

Morten Ruth, the project director for Johan Castberg, told E24 that the shipyard will have to redo about 3,000 linear meters of welding and change four seawater intakes, but it will not require not a major rebuild of the vessel.

"To put this a bit in context, we estimate that the [time] to repair the welds in Singapore, it corresponds to about five percent of the remaining hours [of work], roughly speaking," Ruth said. "This is a lot about organization and getting this done in the right sequence. It is not the volume as such that worries us."

The repair work has been substantially delayed by coronavirus-related slowdowns at Sembcorp, the Singaporean yard building the FPSO, he said. These challenges will likely set Johan Castberg's deployment back by about one year.