This incident occurred in the well intervention derrick on the platform while rigging down after a coiled tubing operation. A heave compensator attached to a length of riser was being lifted when it thumped against an open deck hatch with attached gratings and knocked off one of the grating plates.
The grating fell eight metres and grazed a person working in the area below, who suffered pain and swelling in one shoulder.
In slightly different circumstances, the incident had the potential for a fatal outcome or for causing serious personal injury and substantial material damage. The grating could have fallen further to the underlying decks, where personnel and hydrocarbon systems were present.
A number of barrier breaches have been identified by the PSA’s investigation. The impression is that several barriers failed simultaneously. Several of these are fundamental in nature, such as risk assessment, planning and expertise. While design weaknesses have been identified with the deck hatch, most of the barrier breaches relate to organisational and operational elements.
The investigation has identified nonconformities relating to technical integrity, follow-up, identification of risk, assignment of roles and responsibilities, and governing documents.
The PSA has asked operator company Statoil to explain how the nonconformities will be dealt with.
The Heidrun field lies in some 350 metres of water on the Halten Bank in the Norwegian Sea. It has been developed with a floating concrete-hulled tension-leg platform (TLP) installed over a subsea template with 56 well slots. On stream since 1995, the field is operated by Statoil.