Thursday, June 3, 2010

Thoughts on the BP Oil Spill

It goes without saying that the explosion of the Deepwater Horizon drilling rig and subsequent gushing of oil from the seafloor has saturated the news recently. Six weeks later, with no solution in place, many of us are feeling frustrated, even exasperated, at the lack of progress and at BP's inability to fix the mess it created. Tempers in the public, in the blogosphere, and within the Obama administration are flaring, with one question predominant: Why can't BP plug a damn hole on the bottom of the ocean?

It seems everyone wants to lend an opinion on the best way to fix the broken well (for an excellent list of the operations already attempted, go here). I've heard everything from dropping a giant sandbag on the wellhead to stuffing the bodies of BP CEO Tony Hayward and the totally-unconnected Dick Cheney into the well at ultra-high pressure.

Not a good time to be this man (Tony Hayward), but at least he's too skinny to realistically stop the flow of oil if his body were to be shoved into the well.

Unfortunately, in a bad little bit of public relations by BP, the American public has yet to grasp how excruciatingly difficult conducting operations on the seafloor are, especially when you are tied to a specific point (such as a gushing wellhead). I recently had the opportunity to conduct coring operations for my climate change research in 7000 feet of water (approximately two thousand feet deeper than the Deepwater Horizon's well) and figured I would share some of the lessons I learned from working in such deep water.

1. It takes quite a long time to get to the bottom of the ocean. Every single item that BP deploys to the ocean floor, whether it be a robot, containment dome, or massive saw, has to be lowered down with a winch (it is not simply left to fly with gravity!) The ship I worked on, the R/V Oceanus, had a trawl winch with 30,000 feet of high-tension steel cable, but was limited to lowering equipment at 150 feet per minute. While that's fast, you are still talking more than half an hour to get just a single piece of equipment to the seafloor at the depth of the Deepwater Horizon well. Every instrument swap or failure requires a half an hour to be raised to the surface, then another half an hour for a replacement to be lowered.

2. Lowering a piece of equipment to a precise spot on the ocean floor from a rocking boat and with ocean currents going every which way is not a simple procedure. This should be pretty obvious, but here's an example. Say your friend is lost in the woods and calls you with his exact location, asking to be picked up. How easy would it be to find him, even if you have an excellent GPS system? Oh yeah, and you're blindfolded, because you can't see anything in the ocean below 200 feet of depth. And you're stumbling around drunk, because ships rock on the ocean surface. I think you get my drift.

3. The pressure effect. Where we stand now, the pressure we face is a result of the weight of the overlying air, which adds up to 1 atmosphere. At 5000 feet depth in the ocean, the weight over the overlying water is about 150 atmospheres, or 150 times greater than at the surface of the earth.

This same analysis explains why the oil is currently flowing out at a (maximum) rate of 19,000 barrels per day, or 800,000 gallons per day (if that was all gasoline, that would be enough gas to drive a Toyota Prius, at 55 mpg, 44 million miles, or almost halfway to the sun. If you could drive in space and whatnot).

When the rig exploded, it was reportedly drilling 13,000 feet below the seafloor. To figure out what pressure this oil is under, we need to know the weight of the overlying rock and the water, which we know is 150 atmospheres. Rock is about 2.5 times denser than water, so it is about 2.5 times heavier; therefore, every foot of overlying rock increases the pressure of the oil 2.5 times more than a foot of water. So 13,000 feet of rock would add 1080 atmospheres of pressure. In other words, the oil that is currently gushing out from the Deepwater Horizon well is under 1230 atmospheres of pressure, or is pressurized over twelve hundred times greater than if at the surface of the earth.

This is why the well is gushing like a bunch of fire hoses, and why sealing it off is not a trivial operation. I'm not condoning BP's actions; they should have had a procedure in place, other than the blowout preventer, to avert such an ecological and economic disaster. But when they say that "this procedure has never been tried before at 5,000 feet", it is not a punch line. It is legitimately very difficult to deal with anything at 5,000 feet of depth, let alone a fluid gushing out at twelve hundred times surface pressure.

In short? Don't bother second guessing the BP scientists; there are very few people in the world who know the true difficulties of troubleshooting an accident under these trying conditions. But also don't expect much in the way of progress. Sadly, it looks like the Deepwater Horizon is going to keep on gushing until a relief well is finished drilling in August.

Maybe now we can reconsider what a ludicrous idea "drill, baby, drill" was. Such a careless attitude toward such a dangerous procedure can have devastating consequences. Unfortunately, we will be learning firsthand many of them in the coming months and years.




  2. Well done. While I think it is important to know the difficulty they face, this should really enforce the fact that such a risky endeavor requires much more non-corrupt oversight and greater weighing of potential costs. Here's a good article: