Production at Shell’s Pierce oil and gas field in the UK North Sea has been shut in since late August due to a problem with the mooring system on the field’s floating production, storage and offloading vessel.

Aurelia Energy, the holding company of the Bluewater Group which owns the Haewene Brim FPSO, said in its quarterly report on Thursday that two of the mooring legs on the floater were not properly secured to the buoy and production was stopped.