Code red part 3. Statoil failed the test
As a result, all personnel without emergency duties were ordered to the lifeboats, where they had to remain strapped in for more than two hours. About 100 people were affected. The Petroleum Safety Authority’s (PSA) investigation concluded that personnel in the area could have faced life-threatening danger had the gas ignited.[REMOVE]Fotnote: Ptil. 2011. Granskingsrapport. Gasslekkasje på Gullfaks B 4.12.2010.
The maintenance work on the choke valve was part of planned, routine efforts to detect wear on the valve and production tubing. During leak testing, however, the wrong valves were opened, allowing gas to leak up into the well area and further out through an open drain valve. Operators attempted to stop the leak, but several misjudgements meant that the automatic emergency shutdown system, which would otherwise have quickly halted the leak, was deactivated. In total, 730 kilograms of gas leaked from the well system within an hour.
Statoil’s own investigation concluded that human error, combined with weak planning and poor procedural compliance, were decisive factors. It was noted that if operators had not attempted manual intervention, the automatic safety system would have been activated and the leak stopped rapidly. The maintenance crew were insufficiently familiar with the procedures, and a series of shortcomings in planning and leadership involvement were identified.[REMOVE]Fotnote: Equinor. (2011.1. februar). Granskingsrapport. Gasslekkasje på Gullfaks B. file:///C:/Users/trude.meland/Downloads/GullfaksB_endelig_rapport_frigitt%20(1).pdf
Statoil itself assessed the probability of ignition as low, but acknowledged that the incident could have had far more serious consequences if the leak had continued, or if an ignition source had been present.
The PSA’s investigation examined the underlying causes and pointed to major shortcomings in maintenance planning. The Authority concluded that decision-making processes in the team carrying out the work were inadequate, and that there were serious weaknesses in communication and risk understanding.
The incident was also viewed in light of previous near-misses in Statoil, including the serious gas leak on Gullfaks C earlier the same year. The PSA expressed concern that improvement processes initiated by Statoil after earlier incidents appeared to have had limited effect. The Authority therefore questioned Statoil’s ability – and willingness – to learn from its own mistakes and implement lasting improvements in the organisation.
A difficult lesson
The gas leaks on Gullfaks in 2010 revealed deep systemic weaknesses in Statoil’s management of safety and risk. The incidents – on Gullfaks C in May and Gullfaks B in December – triggered extensive investigations within Statoil, by the PSA, and by external research bodies. Together, the aftermath revealed a company struggling to learn from past mistakes and to implement lasting improvements in safety management.
After the Gullfaks C leak in May 2010, Statoil submitted its internal investigation report to the PSA. However, the PSA was criticised for not initiating its own independent investigation immediately after the incident, despite its catastrophic potential.[REMOVE]Fotnote: SAFE. (2010.18. november). Politisk kritikk av Ptil etter Gullfaks C-hendelsen. Politisk kritikk av Ptil etter Gullfaks C-hendelsen – SAFE
It was only after Statoil presented its report in November 2010 that the PSA began its own inquiry, while simultaneously halting all drilling activities on Gullfaks A, B, and C.
The PSA’s main conclusions largely coincided with Statoil’s findings.[REMOVE]Fotnote: Petroleumstilsynet. Revisjonsrapport. Tilsynsaktivitet med Statoils planlegging av brønn 34/10-C-06A
Planning of the C-06A drilling operation was marked by serious and systematic shortcomings. Risk assessments were inadequate, relevant expertise was not involved, and leadership failed in its follow-up. The Authority stressed that it was largely down to chance that the incident did not escalate into a major accident.
The PSA also pointed out that Statoil had not learned sufficiently from earlier serious incidents, particularly the gas blowout on Snorre A in 2004.[REMOVE]Fotnote: Petroleumstilsynet. Revisjonsrapport. Tilsynsaktivitet med Statoils planlegging av brønn 34/10-C-06A: 11.That event is regarded as one of the most serious on the Norwegian shelf, where an uncontrolled subsea gas leak could have resulted in an explosive fire with potentially catastrophic consequences.[REMOVE]Fotnote: Tinmannsvik, R.K., Albrechtsen, E., Bråtveit, M. (UiB), Carlsen, I.M., Fylling, I. (MARINTEK), Hauge, S., Haugen, S. (NTNU), Hynne, H., Lundteigen, M.A. (NTNU), Moen, B.E. (UiB), Okstad, E., Onshus, T. (NTNU), Sandvik, P.C. (MARINTEK) og Øien, K. (2011, mai). Deepwater Horizon-ulykken: Årsaker, lærepunkter og forbedringstiltak for norsk sokkel. SINTEF.
On 28 November 2004, an uncontrolled gas blowout occurred from injection well P-31A on the Snorre A platform. Gas rose through the well and bubbled up beneath the platform, and at one point concentrations came dangerously close to the explosive limit. Extremely heavy drilling mud was pumped down – a manoeuvre known as ‘bullheading.’ After nearly half a day of intense work, the blowout was stopped. The incident is considered one of the most serious near-misses on the Norwegian shelf
The Snorre A investigation uncovered systemic failures, including poor compliance with governing documents, flawed risk assessments and inadequate leadership involvement — findings that closely matched those later seen after the Gullfaks incident.[REMOVE]Fotnote: Petroleumstilsynet. Gransking av gassutblåsning på Snorre A, brønn 34/7-P31 A 28.11.2004. https://docplayer.me/17110888-Rapport-gransking-av-gassutblasning-pa-snorre-a-bronn-34-7-p31-a-28-11-2004.html
At Gullfaks, the PSA identified 40 regulatory breaches related to the drilling operation.[REMOVE]Fotnote: Petroleumstilsynet. Revisjonsrapport. Tilsynsaktivitet med Statoils planlegging av brønn 34/10-C-06A. Statoil was ordered to examine why such serious deviations had not been detected earlier. Despite these findings, the PSA chose not to report the company to the police.[REMOVE]
Fotnote: Aftenposten 24. november 2010The police nevertheless launched their own investigation, and in 2013 the prosecutor in Rogaland imposed a fine of NOK 30 million on Statoil.[REMOVE]Fotnote: Aftenposten. (2013. 20. mars). Statoil fikk kjempebot etter nestenkatastrofe.
At the same time, the PSA ordered Statoil to conduct a thorough study of the underlying causes of the Gullfaks C incident. The assignment was given to the International Research Institute of Stavanger (IRIS), with a clear mandate to assess Statoil’s capacity to learn from past mistakes. The aim was to identify organisational, cultural, and structural factors that had contributed to weakened risk management.[REMOVE]Fotnote: IRIS. Læring av hendelser i Statoil. En studie av bakenforliggende årsaker til hendelsen på Gullfaks C og av Statoils særingsevne. Rapport IRIS – 2011/156.
The IRIS study highlighted several underlying causes. In particular, the 2007 merger between Statoil and Hydro’s oil and gas division was cited as a source of major organisational challenges, affecting corporate culture, communication and cooperation. Staffing and organisational changes ahead of the incident had weakened leadership capacity and decision-making in operational situations. The study also revealed inadequate communication and documentation, meaning critical information was not properly shared or followed up.
The study confirmed a recurring lesson from safety work in the petroleum industry: while direct causes of incidents vary, the underlying reasons are often the same. Inadequate verification of well barriers, poor risk assessment when changes are made, weak leadership involvement and low organisational learning capacity were among the most prominent challenges Statoil faced.
The review underlined the need for a far more systematic approach to risk management, stronger leadership commitment to safety, and an organisational culture capable of learning effectively from previous incidents.