BP’s Deepwater Horizon oil disaster in the Gulf of Mexico was not caused by a single factor but by “multiple companies and work teams,” according to the oil giant’s internal investigation.
BP’s report concludes that a sequence of failures involving a number of different parties including BP, Halliburton and Transocean led to the explosion and fire which killed 11 people and caused widespread pollution in the Gulf of Mexico earlier this year.
According to the report, 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 BP internal report found that:
- The cement and shoe track barriers – and in particular the cement slurry that was used – at the bottom of the Macondo well failed to contain hydrocarbons within the reservoir, as they were designed to do, and allowed gas and liquids to flow up the production casing;
- The results of the negative pressure test were incorrectly accepted by BP and Transocean, although well integrity had not been established;
- Over a 40-minute period, the Transocean rig crew failed to recognize 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;
- Even after explosion and fire had disabled its crew-operated controls, the rig’s blow-out preventer on the sea-bed should have activated automatically to seal the well. But it failed to operate, probably because critical components were not working.
“To put it simply, there was a bad cement job and a failure of the shoe track barrier at the bottom of the well, which let hydrocarbons from the reservoir into the production casing. The negative pressure test was accepted when it should not have been, there were failures in well control procedures and in the blow-out preventer; and the rig’s fire and gas system did not prevent ignition,” said BP’s outgoing chief executive Tony Hayward, who commissioned the investigation.
Hayward said that based on the report, “it would appear unlikely” that the well design contributed to the accident. The investigation found that the hydrocarbons flowed up the production casing through the bottom of the well.
The investigation team has proposed a total of 25 recommendations designed to prevent a recurrence of such an accident. The recommendations are directed at strengthening assurance on blow-out preventers, well control, pressure-testing for well integrity, emergency systems, cement testing, rig audit and verification, and personnel competence.
The company said it expected a number of the investigation report’s findings to be considered relevant to the oil industry more generally and for some of the recommendations to be widely adopted.
BP’s incoming chief executive Bob Dudley said BP has accepted all of the report’s recommendations and is examining how best to implement them worldwide.
BP said the report was based on information available to the investigating team. It noted that additional relevant information may be forthcoming, for example, when Halliburton’s samples of the cement used in the well are released for testing and when the rig’s blow-out preventer is fully examined now that it has been recovered from the sea-bed. There will also be additional information from the multiple ongoing U.S. government investigations.
The report is unlikely to halt the blame shifting that has been going on over the Gulf disaster or stem the litigation.
In testimony before Congress In June, several workers on the Deepwater Horizon blamed BP management for the spill, maintaining they cut corners and neglected safety issues in order to increase profits.
Drilling company Transocean, which BP has argued is partly responsible, has attempted to distance itself from the disaster and limit its liability.
Another BP partner on the rig, Anadarko Petroleum, has accused BP of “willful misconduct” and said BP is entirely to blame for the disaster.
BP has spent $8 billion thus far responding nto the Gulf disaster.
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