Why so hard to plug oil leak in the Gulf of Mexico?

EarthSky listeners have been asking why it’s so hard to plug oil leak in the Gulf of Mexico. We asked biogeochemist Mandy Joye. She said the answer mostly has to do with pressure.

Mandy Joye: I envision it in my mind as trying to cap a volcano.

Dr. Joye, of the University of Georgia, has studied the waters of the Gulf region for 15 years.

Mandy Joye: When you think about this oil spill, there’s one piece of critical information that I think will put it in perspective. And that is that the reservoir from which this oil and gas is flowing is 4 kilometers – kilometers! – below the sea floor.

That’s about two and a half miles. She explained that the oil and gas at the bottom of the well is under tremendous pressure and it wants to escape to the top of the well, at the floor of the Gulf.

Mandy Joye: That pressure gradient is what’s driving the flow out of this well, and it’s pushing through this tiny opening on the sea floor.

That tiny opening is a pipe about 20 inches in diameter. Dr. Joye said the oil reservoir miles beneath the surface of the Earth is tens of thousands of times bigger than this pipe, making the pressure so great, she said, it’s impossible to do a quick-fix of the situation.

Mandy Joye warns of danger of methane gas in Gulf oil plumes

Mandy Joye: We don’t know really whether that pipe is intact. If you cap that pipe you could actually over pressurize the system and damage the pipe and then and then you’ve really caused a problem. Drilling relief wells to reduce the pressure is in my opinion the best way to reduce the amount of oil and gas leaking into the system. But that’s a solution that takes months to put on the table.

She added that the pressure the oil is under is affecting how it’s being dispersed underwater. There’s a lot rising to the surface, but much of the estimated hundreds of thousands of barrels of oil that have poured into the Gulf are diluted underwater.

Mandy Joye: If you put olive oil in a can and you pressurize that can, what happens? It comes out as a mist. That’s sort of how you can imagine the oil coming out of this well. The stuff that’s just floating around in the deep water are fine particles of oil and dissolved methane.

Joye said that while this spill is a disaster compounded by human error and the mechanics of the Earth itself, we humans need to consider how we’ve collectively contributed.

Mandy Joye: For me as an oceanographer and as an inhabitant of this planet, I would hope that everyone takes a hard look at their own personal energy use. I think the message of this oil spill should be: fossil fuels are not free. There’s a cost at the gas tank, there’s a cost when you pay your power bill, and there’s a potentially catastrophic environmental cost. And we can’t afford that.

Jeff Masters on when a hurricane meets the Gulf oil spill