Deepwater horizon: what went wrong
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1 2 3 4 5 6 7 8 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 1 The cement and valve at the bottom of the drill pipe failed to stop oil and gas bursting into the well pipe 2 Well pipe metal casing Oil and gas Oil and gas Cement fills ‘annulus’ gap Float collar (one-way valve) and shoe track cement Shoe track Well pipe Failed Failed What went wrong? The BP report identifies eight key elements in the Deepwater Horizon drilling operation - each of which could have prevented the disaster Staff misread a key pressure test thinking high readings were an error 3 Oil and gas were now pouring up the well, but it took 40 minutes for this to be noticed 4 Once oil and gas started flooding to the surface, they were not diverted overboard but swept on to the rig 5 Riser carries oil to rig Blowout preventer Oil and gas flowing unnoticed Failed Oil and gas should have been directed overboard Failed The oil and gas ‘vented directly on to the rig’. This made an explosion was inevitable 6 Cloud of gas spreads around the rig and under the deck Failed The fire prevention system on the rig failed. The report says the ‘heating, ventilation and air conditioning system … transferred a gas-rich mixture into the engine rooms’. Two huge explosions followed, killing 11 crew members 7 The ‘failsafe’ blowout preventer (BOP) failed. Fire on the rig stopped it being remotely shut down, while an automated system also failed. The BOP had flat batteries in one control pod and a faulty solenoid valve in another 8 Failed Gas ignites, destroying the rig 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 Multiple cutoff devices should have shut off the flow of oil and gas automatically Failed 19 April 7.30pm–12.36am 20 April 4.50pm 20 April 7.55pm 20 April 9.56pm 20 April 8.50pm 20 April 9.40pm 20 April 9.49pm Sea floor at 5,000 feet Oil-bearing rock at 18,000 feet SOURCE: BP DRAWINGS NOT TO SCALE The key times Report: ‘There were weaknesses in cement design’ Report: ‘The investigation team identified … failure’ Report: ‘Site leaders reached the incorrect view’ Report: ‘Weaknesses in the testing regime and maintenance management’ Report: ‘Rig crew did not recognise the influx’ Report: ‘This overwhelmed the … system’ Report: ‘If fluids had been diverted overboard … consequences may have been reduced’ Report: ‘The fire and gas system did not prevent … ignition’ Failed Blowout preventer Drill pipe Deepwater Horizon rig Riser
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The BP report into the Deepwater Horizon explosion is out - here are the key findings
Transcript of Deepwater horizon: what went wrong
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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
1 The cement and valve at the bottom of the drill pipe failed to stop oil and gas bursting into the well pipe
2
Well pipe metalcasing
Oil and gas Oil and gas
Cement fills ‘annulus’ gap
Float collar(one-way valve)and shoe trackcement
Shoetrack
Well pipe
FailedFailed
What went wrong?
The BP report identifies eight key elementsin the Deepwater Horizon drilling operation - each of which could have prevented the disaster
Staff misread a key pressure test thinking high readings were an error3 Oil and gas were now pouring up the
well, but it took 40 minutes for this to be noticed
4
Once oil and gas started flooding to the surface, they were not diverted overboard but swept on to the rig
5
Riser carries oil to rig
Blowoutpreventer
Oil and gas flowing unnoticed
Failed
Oil and gas should have been directed overboard
Failed
The oil and gas ‘vented directly on to the rig’. This made an explosion was inevitable
6
Cloud of gas spreads around the rig and under the deck
Failed
The fire prevention system on the rig failed. The report says the ‘heating, ventilation and air conditioning system … transferred a gas-rich mixture into the engine rooms’. Two huge explosions followed, killing 11 crew members
7 The ‘failsafe’ blowout preventer (BOP) failed. Fire on the rig stopped it being remotely shut down, while an automated system also failed. The BOP had flat batteries in one control pod and a faulty solenoid valve in another
8
Failed
Gas ignites, destroying the rig
Key test involved filling the kill line to check pressureon the drill. Because the line was blocked, no fluids escaped - leading staff to assume everything was working correctly
Multiple cutoffdevices shouldhave shut off the flow of oil and gasautomatically
Failed
19 April 7.30pm–12.36am
20 April 4.50pm
20 April 7.55pm
20 April 9.56pm
20 April 8.50pm
20 April 9.40pm 20 April 9.49pm
Sea floor at 5,000 feet
Oil-bearing rock at 18,000 feet
SOURCE: BP DRAWINGS NOT TO SCALE
The key times
Report: ‘There were weaknesses in cement design’
Report: ‘The investigation team identified … failure’
Report: ‘Site leaders reached the incorrect view’
Report: ‘Weaknesses in the testing regime and maintenance management’
Report: ‘Rig crew did not recognise the influx’
Report: ‘This overwhelmed the … system’
Report: ‘If fluids had been diverted overboard … consequences may have been reduced’
Report: ‘The fire and gas system did not prevent … ignition’
Failed
Blowoutpreventer
Drill pipe
Deepwater Horizonrig
Riser
