Sunday, May 9, 2010

The BP Oil Spill Was Not an Accident

Yesterday, as I was writing a post about the role of methane hydrate crystals in the oil spill containment efforts, a consensus had already formed among engineers and experts that the same methane hydrate crystals that caused the silo to fail also caused the original explosion and oil leak. This means that the oil leak was not an accident at all, but the inevitable result of the technology that was being employed.

If a tree falls in a minefield and causes some of the mines to go off, that is not an accident — it’s something you expect if you put a minefield near trees. Similarly, the BP explosion was not an accident. If the explosion had not occurred on the day it did, it would have occurred the next day, or the next week. The explosion was going to occur, and soon, and there was nothing anyone could have done to stop it, except to not drill the oil well.

To explain this, I have to explain the physical nature of methane hydrate crystals. Methane is a familiar hydrocarbon that forms naturally wherever plants decay. It is usually known as natural gas. In the atmosphere and in the upper levels of the ocean, it is a gas. Under very high pressure in the presence of water, however, methane forms a solid crystal, and that’s what happens on the sea floor under about 500 meters of water.

This is a highly unstable situation, however, because methane in this solid form is lighter than water and tends to rise as soon as it can work its way loose from whatever mud or other material is holding it in place on the sea bottom. As it rises, the water pressure around it falls, and when the pressure falls enough, the methane turns to gas in an explosion. This is not the same as the explosions that you hear about from time to time when natural gas breaks free from a container and catches fire. In that situation, it is the combustion that causes the explosion. There is no fire in the explosion of methane hydrate crystals. Just the fact of the methane converting from solid to gas is enough to create an explosion. However, the methane gas then bubbles up to the surface, and if it encounters the slightest spark, then it will catch fire and create a second explosion. This, apparently, is the sequence of events that occurred in the BP oil platform. There was a rush of methane into the platform, under so much pressure that workers were injured by flying furniture. A fire occurred. But the oil spill is not the result of the fire, but the result of the original underwater explosion.

Was it a freak accident that methane and crude oil happened to be in the same place? Hardly. You expect to find methane and crude oil together. They are both hydrocarbons. They are created together by the same geological processes. Wherever you drill for oil, you expect to get methane mixed in, and if you drill in deep enough water, you would have to expect the methane to be in solid form.

Yet this is not what BP planned on. Its deep-water oil well was drilled using the same technology that is used for drilling in shallow water. Engineers are still trying to figure out what to do about the methane hydrate crystals. There has to be a mechanism to separate the methane from the crude oil at the sea floor, before anything is brought up to a higher level where the water pressure is less and the methane will explode. Yet no such technology exists.

BP has started work on a relief well, which will duplicate the effects of the original well, and will therefore run into the same problem of exploding methane. It will be extraordinarily good fortune if the relief well can operate for any longer than the original well did, since it is drilling into the same oil reservoir with the same methane mixed in.

All this means that we currently have no plan whatsoever to contain an oil spill that, at the rate it is going, will cover the entire Gulf of Mexico by the end of the year. If the relief well fails in the same manner, it will double the rate of the oil leak, without providing any added control over the oil.

Yet no plan doesn’t mean it won’t happen. This is a solvable problem. Fundamentally what is needed is a refinery-style device, a giant filter that can separate crude oil from methane at the sea floor and direct them up to the surface separately. If we had known what we know now, this would have been part of the original design for the oil well. The physical nature of methane hydrate crystals has been reasonably well known for 25 years, so it would have been prudent to design with them in mind in the first place. It is unfortunate that both BP and the U.S. Department of Energy thought it was a good idea to conduct an experiment on this scale with such ill-prepared technology, when we could have simply waited until the right technology was available.

But we no longer have that choice. Prior to this event, if someone had told me, “We’re going to create a simple kind of refinery and operate it on the sea floor,” I would have said that it was a crazy idea that would never work. But now it has to work — unless someone has a better idea.