With the blown Macondo well essentially sealed, and with the oil remaining under the water dissipating (though to uncertain ecological effects), focus is now turning to the ongoing investigations into the cause of the biggest oil spill in U.S. history. Wednesday morning BP released the results of its own internal investigation into the catastrophe on the Deepwater Horizon rig, and the conclusion is basically this: a lot of things went wrong, most of which wasn’t our fault, and if you want to blame anyone, blame Halliburton and Transocean for their crappy cementing job and drilling oversight. Or as BP’s departing CEO Tony Hayward put it in more politic terms:
The investigation report provides critical new information on the causes of this terrible accident. It is evident that a series of complex events, rather than a single mistake or failure, led to the tragedy. Multiple parties, including BP, Halliburton and Transocean, were involved.
You can read the entire report here, but the main points from BP’s investigative team can be found below:
- 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 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;
- 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.
BP’s report underscores what company executives like Hayward have said over the past several months: though BP may be financially responsible for the spill, much of the operational blame should be shifted onto its corporate partners. BP officials on the Deepwater Horizon made mistakes—including misreading the well pressure data that might have indicated an explosion was about to occur—but the greater errors were made by companies like Halliburton, responsible for cementing the well, and Transocean, which operated the rig. If nothing else BP’s report—completed over the past four months—provides a blueprint for how the company will defend itself in the many, many legal cases that will stem from the disaster. Anyone expecting BP to take full responsibility for the spill will be disappointed—instead you’ll likely see the major companies squabbling amongst themselves over who did what and when, repeating in the courts what their bickering chief executives said before Congress shortly after the spill began.
One finding from BP’s report, if it holds up, could be significant: the company’s team says that the uncontrolled rise of natural gas caused by the blowout came up the center of the drilling pipe, not the outer casing (also known as the annulus). BP has been criticized for a using a well casing on the Deepwater Horizon that documents show company officials knew was cheaper but less stable—if it turns out the casing didn’t play a major role in the blowout, BP might escape some of the blame coming its way. Indeed, the market reacted positively to the report, with BP’s stock rising in the hours after the investigation’s release.
But BP’s report is just one of many investigations that will be made public over the next several months—the Bureau of Ocean Energy Management, Regulation and Enforcement and the Coast Guard have their own independent inquiries pending. The original, failed blowout preventer—which BP wasn’t able to examine for its report—was just recovered and could provide valuable evidence for the forthcoming investigations. Still, given the sheer complexity of the accident and the confusion surrounding the events of April 20, there will likely never be a final, single answer that will satisfy everyone. BP is right in this at least—the disaster at Deepwater Horizon had many parents. “At the end of the day, all right of these things had to occur to get from the initiation of this to the end of the accident,” said Mark Bly, BP’s safety chief and the head of the investigative team, at a briefing Wednesday morning. That’s a more technical way of saying that bad luck played a major role—which makes me wonder, at least, how much more bad luck might be waiting for us in the Gulf of Mexico.