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Probe finds Macondo BOP activated
A forensic investigation of the failed Macondo well blowout preventer has determined that the device did activate during the course of the explosion and fire on the Deepwater Horizon rig in the Gulf of Mexico in April 2010. The investigation report, published by Det Norske Veritas, the company retained to conduct the investigation, says that the BOP rams, including the blind shear rams that should have cut through the well’s drill pipe, hence sealing it off, did operate following the well blowout. But the blind shear rams failed to completely close, the report says.
The investigation, conducted in a NASA facility in New Orleans, involved a detailed examination of the blowout preventer, and of the remains of the drill pipe that had passed through the device. The investigators matched up broken segments of pipe visually and using laser-generated profiles, and then reconstructed the events within the blowout preventer before, during and after the blowout.
Pipe buckled It appears that as the blowout gained momentum it pushed the drill pipe inside the blowout preventer up against a closed device called the upper annular, towards the top of the preventer. The force of the blowout then caused the pipe to buckle into a configuration where it was resting against the side of the well bore. Then, when the blind shear rams activated, the buckled pipe was only part way within the span of the ram blades. As a consequence, the ram blades only partially cut the pipe, causing part of the pipe cross section to become trapped in the ram mechanism, thus preventing the ram blades from fully closing.
Although the investigation appears to have shed much needed light on the cause of the blowout preventer failure, the investigators are still not exactly certain when the blind shear rams activated. However, since the buckling of the drill pipe would have happened in the initial stages of the incident, the timing of ram activation did not impact the end result, the report says.
—Alan Bailey
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