The BP report identifies eight key elements in the Deepwater Horizon drilling operation each of which could have prevented the disaster The key times
20 April 9.40pm Report: ‘This overwhelmed the … system’ 20 April 9.49pm Report: ‘The fire and gas system did not prevent … ignition’
1 The cement that was supposed to stop oil and gas reaching the well pipe casing did not work. The report blames the type of cement used
Well pipe metal casing Cement fills ‘annulus’ gap
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2 The cement and valve at the bottom of the drill pipe failed to stop oil and gas bursting into the well pipe
Float collar (one-way valve) and shoe track cement Well pipe
Deepwater Horizon rig
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Report: ‘If fluids had been diverted overboard … consequences may have been reduced’
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Shoe track
Oil and gas Riser
Oil and gas
3 Staff misread a key pressure test thinking high readings were an error
20 April 8.50pm Report: ‘Rig crew did not recognise the influx’
4 Oil and gas were now pouring up the well, but it took 40 minutes for this to be noticed 4
Riser carries oil to rig
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Key test involved filling the kill line to check pressure on the drill. Because the line was blocked, no fluids escaped - leading staff to assume everything was working correctly 20 April 7.55pm Report: ‘Site leaders reached the incorrect view’ Sea floor at 5,000 feet
Oil and gas flowing unnoticed Blowout preventer
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20 April 9.56pm Report: ‘Weaknesses in the testing regime and maintenance management’
Blowout preventer
Once oil and gas started flooding to the surface, they were not diverted overboard but swept on to the rig
Drill pipe
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6 The oil and gas ‘vented directly on to the rig’. This made an explosion was inevitable il Fa
Cloud of gas spreads around the rig and under the deck
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Oil and gas should have been directed overboard
7 The fire prevention system on the rig failed. The