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BP publishes internal investigation report on Gulf of Mexico explosion
The report prepared by the BP internal investigation team has been published. You can view the Executive Summary or view all All Published Material.
The report is based on a four-month investigation led by Mark Bly, BP’s Head of Safety and Operations and conducted independently by a team of over 50 technical and other specialists drawn from inside BP and externally. The investigation found that:
“no single factor caused the Macondo well tragedy. Rather, a sequence of failures involving a number of different parties led to the explosion and fire which killed 11 people and caused widespread pollution in the Gulf of Mexico earlier this year”.
The report concludes that decisions made by “multiple companies and work teams” contributed to the accident which it says arose from “a complex and interlinked series of mechanical failures, human judgments, engineering design, operational implementation and team interfaces.”
The specific sequence of events leading to the disaster were:
- cement slurry at the bottom of the Macondo well failed to contain hydrocarbons within the reservoir, as it was designed to do, and allowed gas and liquids to flow up the production casing;
- results of the negative pressure test were incorrectly accepted by BP and Transocean, although well integrity had not been established;
- Transocean rig crew failed to recognise and act on the influx of hydrocarbons into the well until the hydrocarbons were in the riser and rapidly flowing to the surface;
- after the well-flow reached the rig it was routed to a mud-gas separator, causing gas to be vented directly on to the rig rather than being diverted overboard;
- the flow of gas into the engine rooms through the ventilation system created a potential for ignition which the rig’s fire and gas system did not prevent;
Comment
The specific events leading to the fire and death of those on the rig were a mixture of human and technical ‘failures’. This will be a familiar finding to those who have investigated construction project fatalities and other incidents. There has been an increasing emphasis on ‘human factors’ across the oil, gas and construction industries in recent years.
The final safety precaution to fail involved the rig blow-out preventer (BOP) on the sea-bed. The BOP, which should have activated automatically to seal the well, failed to operate ”probably because critical components were not working” (see Main Report page 178). More critically, the report concludes that:
“through a review of rig audit findings and maintenance records, the investigation team found indications of potential weaknesses in the testing regime and maintenance management system for the BOP.”
This brief comment highlights a general lesson for all businesses. It is relatively easy to establish ‘management systems’ designed to secure the effective control of human and environmental risks. The more difficult task is sustaining those systems in the face of other demands – before things go wrong.
In the construction sector a key foundation of CDM 2007 is the requirement that contractors plan, manage and monitor risks and project safety plans. The Deepwater Horizon incident highlights the importance of a monitoring regime and culture that is positive, rigorous and constantly revitalised.