SCOTT SIMON, Host:
This is WEEKEND EDITION from NPR News. I'm Scott Simon.
The well in the Gulf of Mexico stopped spewing oil more than a day and a half ago, but officials aren't sure that they can keep it shut down. Tests of the well has given them ambiguous results. The concern is that now that the top of the well is closed off, oil could potentially cut a new path to the surface through rock and mud.
NPR science correspondent Richard Harris joins us in our studios.
Richard, thanks for being with us today.
RICHARD HARRIS: My pleasure, Scott.
SIMON: Key to this seems to be the test results. So could you explain those to us?
HARRIS: Sure. Well, they put this cap on the well on Monday and the cap was capable of forming a tight seal. Thursday, they actually closed all the valves that were on this cap and so they stopped the oil from flowing into the ocean. But they let the pressure from the oil and gas build up inside the well, which, remember, is basically 13,000 feet of steel and cement going down from the seafloor to pretty deep, obviously, under the seafloor.
So they wanted to see what would happen inside that wellbore, as they let this pressure build up - whether it was solid or leaky. And think of it like closing the nozzle on a garden hose to find out whether all the fittings are tight or not. And unfortunately, the pressure results they got were ambiguous.
It seemed as though possibly maybe it wasn't as high as they thought it was. So maybe one possibility was that the well has actually spewed so much oil into the Gulf by now that it's just sort of lost some of its oomph. But the other possibility is that it actually is leaking somewhere.
SIMON: Yeah. Nature finds a way, right? I mean water, or in this case oil, would necessarily spread out and diffuse?
HARRIS: It would try to, absolutely.
SIMON: Yeah. What can they do?
HARRIS: Well, if it's just leaking into the sand all the way at the bottom of the well, that's not such a big deal. But if it's leaking higher up, it could actually be cutting new passages to the surface. And if that's the case, that could be really pretty hard to stop.
And remember, they're going to eventually stop this spewing well by drilling a relief well that will let them pump cement into the wellbore. But they may not be able to pump cement into a whole network of cracks in the rock, if that's indeed what's going on.
SIMON: Okay. And we have a clip from Thad Allen, I guess. Don't we?
HARRIS: Yeah, let me tell you a little bit about that. He was talking about what the options are facing him right now. They've been studying this situation and they were hoping to get a better idea of what's going on down there. And they'd like to leave the well shut, if they can.
But they can also - the other option is they can open up the valves again and relieve this pressure. And that would unfortunately mean - at least for a period of hours or days, or may be even more than a week - that oil would flow once again into the Gulf. So they don't want to do that if they don't have to.
And yesterday at a news briefing Thad Allen did remind everyone that the cap really wasn't put there initially to shut down the flow of oil.
THAD ALLEN: The purpose of the cap and where we're going has always been containment. And the final solution was going to be the relief well. So we shouldn't get so wrapped up in our ability to shut-in the well that we compromise our ability ultimately to have the relief well be successful. And that's the reason we're being so measured moving forward.
SIMON: This is a tough choice. I mean he's essentially saying keep your eye on the prize. And the eye on the prize is ultimately squelching the oil.
HARRIS: That's right. The choice is, you know, they can play it really safe and open up the well. But that would obviously mean more oil into the Gulf. Or they can hope that they've got it right and that actually all that's happening is that the well just doesn't have as much pressure as they thought.
So they are going to keep monitoring really closely. I don't think they're going to resolve this really very quickly. But they'll just keep watching and being really careful.
SIMON: Okay. Well, we'll keep watching it too. Thank you so much, Richard.
HARRIS: My pleasure.
SIMON: NPR science correspondent Richard Harris.
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