Fixing the Gulf Oil Leak: Blowout Preventers and Robotic Submarines

Updated June 20

Update:

We are now 62 days into the Gulf of Mexico oil leak, and since this post was first published a number of different attempts to stem the flow have been attempted with varying degrees of success. (They varied from "abject failure" to "capturing some of the oil.")

As estimates of oil flow rates climbed steadily from 5,000 barrels per day up to a stunning 60,000 barrels per day, the strangely-named efforts ramped up. For a few days, the top kill approach seemed promising: this involved injecting large amounts of mud and drilling fluid into the well to stem the flow, but after several days BP admitted defeat.

Next, the company did manage to install a lower marine riser package cap over the top of the damaged blowout preventer. To do this, diamond wire saws were deployed to cut off the damaged pipe; with the new cap then manuevered in place, captured oil and gas are brought up a pipe to a waiting ship, the Discoverer Enterprise. The gas is flared off, and the oil stored. This, along with a secondary siphoning technique using the same equipment used for the top kill injection, now has a maximum capacity of 28,000 barrels per day of captured oil. We're still a ways off from President Obama's promise to be capturing 90 percent of the oil within a short timeframe.

Clearly, the technical difficulties involved with an enormous leak under 5,000 feet of water have been, to this point, nearly insurmountable. Still, the flow of ideas from everywhere, including extensive suggestions in the comments section below, is impressive. Among those ideas are the use of explosive charges (including nuclear, although that option has been largely rejected as "crazy" by officials), installing a heavier blowout preventer capable of withstanding the pressure of the escaping oil, and disconnecting the pipe's flanges and installing an open gate valve.

Though some of the oil is now being captured, such ideas could still play a role before the leak can be shut off completely. Recent reports indicate that drilling of the relief wells is ahead of schedule, but BP still estimates they won't be fully operational until August. By then, this spill will have become among the worst the world has ever seen.

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When the Deepwater Horizon offshore oil rig exploded on April 20, much of the oil that was actually on the rig ended up in the water. We have since learned that as far as oil spillage is concerned, this was not the problem. The problem actually lies 5,000 feet under water, where the well from which Deepwater Horizon was pulling oil has since been spewing about 5,000 barrels, or 210,000 gallons, of oil each day. The thing is, the rig actually had a piece of technology that should have prevented this. It didn't work.

Oil wells both on and offshore have contraptions called blowout preventers. Those iconic old images of oil well gushers? The blowout preventer stops that from happening, saving much cleanup and money given all the oil that used to spew randomly all over the place before it could be brought under control. According to BP's CEO Tony Hayward, the blowout preventer should have kicked in the day that the explosion occurred, but failed to do so. They don't seem to know why.

Because the 450-ton blowout preventer (a bigger, underwater version of the image to the right, below) still does sit atop the leaking well, option A for stemming the flow of oil has been to kick it into action. To do so, BP has sent in remote-controlled submarines with robotic arms. As cool as that sounds, it too has failed, and again we don't quite know why.

Another less catchy option for preventing further leakage into the Gulf is to create chambers to sit around the three leaks, and connect pipes from those chambers that will funnel the oil up to the surface. Makes sense, but it will take at least a few weeks to get it going. And according to CNN, that technique has never even been tested in water so deep.

Finally, BP has one more idea: by this weekend the Transocean Development Driller III will begin work on a "relief-well" nearby that could stem the flow through the leaking well. Good idea, except that one will take up to three months. Let's see, 210,000 gallons per day, up to 90 days... almost 19 million gallons, or more than 61,000 tonnes, not even including what has leaked so far. If we get to that point, the constant comparisons to Exxon Valdez won't be so hyperbolic; that disaster totaled about 35,000 tonnes of oil (although there have been many other larger spills around the world).

This is the second major offshore oil rig incident in less than a year. In 2009, an Australian rig in the Timor Sea spewed oil into the water for 10 weeks before a decidedly low-tech fix stopped the flow: they pumped huge amounts of mud into the well to plug it up.

Pulling oil up from deep underground that is in turn deep underwater is, clearly, a complicated business. Fixing a giant mistake in that process is proving even harder. A spokesman for BP summed up the efforts to stem the river of oil well: "We're not sure it's going to work, but it's certainly something worth attempting."

(Photos via US Coast Guard and Philbentley)

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