How Bad Can The Spill Get?

The Gulf of Mexico oil spill is getting progressively more serious, with the amount of leaked oil growing by 5,000 barrels (200,000 gallons) or more every day. In the three weeks since the Deepwater Horizon oil rig exploded, about 100,000 barrels have been spilled. Tar balls and oiled-up birds are already washing up on the Louisiana shore - and the volume of leaked oil is projected to surpass the 1989 Exxon Valdez spill sometime next month.

The Gulf of Mexico oil spill is getting progressively more serious, with the amount of leaked oil growing by 5,000 barrels (200,000 gallons) or more every day. In the three weeks since the Deepwater Horizon oil rig exploded, about 100,000 barrels have been spilled. Tar balls and oiled-up birds are already washing up on the Louisiana shore - and the volume of leaked oil is projected to surpass the 1989 Exxon Valdez spill sometime next month.

How much worse could it get? A lot worse, according to projections from BP, the oil company responsible for cleaning up the spill. That's why engineers are being careful about what they do to stop the leak.

If the safety equipment installed on the wellhead worked the way it was supposed to, there wouldn't have been a spill at all. A stack of valves and tanks known as a blowout preventer, or BOP, should have slammed the pipe shut as soon as the pressure went out of control. Obviously, that didn't happen, but experts believe that the BOP is reducing if not stopping the flow of oil.

When BP filed its oil-drilling plan for the site, more than a year ago, it estimated that the worst-case scenario would be a blowout leaking 162,000 barrels of oil a day. That's the equivalent of 10 Olympic-size swimming pools, or 32 times as much oil as is leaking right now.

Philip Johnson, a petroleum engineering professor at the University of Alabama, said that estimate is way beyond what could actually happen. He said that amount of oil flow would have to be sparked by a "hugely bizarre event," such as the kind of undersea earthquake you might see in a Clive Cussler thriller. 

"It's an extremely high rate," he told me. "I don't believe that's a realistic upside to that well."

It's hard to judge how close the actual worst-case might come to the bizarrely huge projections, but Johnson guessed that the maximum flow might be 20,000 barrels a day. Last week, BP executives reportedly gave lawmakers a higher figure: 60,000 barrels a day.

The potential for a bigger leak helps explain why BP isn't blowing up the well site with torpedoes or nuclear weapons, even though some msnbc.com users have suggested that course. "My reaction to that is, why would you think that would work?" Johnson said.

What is now a partially controlled wellhead would become a "big crater with a hole coming up from the bottom of it," he told me. "The pipe lying on the floor provides a better opportunity to seal this than an open well."

Plan BP for stopping the leak

Over the weekend, experts tried dropping a containment chamber over the pipe from which most of the oil was leaking. If the chamber worked, the oil mixture could be brought up to the surface for reprocessing. But the effort was stymied because frozen gas and water - a slushy blend known as gas hydrates - clogged the opening at the top of the chamber.

BP is now looking into using a smaller containment chamber, nicknamed a "top hat." Johnson explained that the smaller chamber would cut down on the amount of water mixing with the gas coming out of the pipe. Methanol would be injected into the flow to further inhibit the formation of hydrates.

Another strategy under consideration is to plug up the leaking well from above - perhaps by injecting shredded-up tires, golf balls and other material into the blowout preventer. Such a "junk shot" could plug up any leakage inside the BOP - but it could also create a risky buildup of pressure at the wellhead. In a worst-case scenario, the weakened wellhead could blow its top - and increase the flow of oil.

Johnson said that such a turn of events could occur if the wellhead suffered significant damage. "If that's the case, then that wellhead is going to come off eventually whether or not you put the junk shot in there," he said. "The risks of doing the junk shot are far outweighed by the rewards: stopping the flow, and the sooner the better."

Stopping the flow is not the only front in BP's battle against the leak:

    * Chemical dispersants are being used at the surface and near the source of the leak to turn the oil into a light, viscous "mousse" that can degrade more easily.
    * Miles and miles of booms are being put out to contain the oil at the surface.
    * Fires are being set at sea to burn off some of the oil.
    * Staging areas are being set up in Louisiana, Mississippi, Alabama and Florida to cope with cleanup when oil reaches shore.
    * Fishing-boat operators and others are being recruited to help with the containment effort.
    * Federal, state and local officials are considering a plan to shore up the barrier islands that protect Louisiana's marshlands.

For a long-term fix, BP is drilling a relief well that should intersect with the leaking well 13,000 feet beneath the seafloor. Thick mud and concrete would be pushed down the relief well to plug up the leak for good.

Even if the flow of oil were to increase dramatically, "the strategy would remain completely unchanged," BP spokesman David Nicholas told me. "The response plan that is in place would be the response that would be in place for the worst-case scenario."

How long, and how far?
One factor that could make the worst-case scenario even worse is the possibility that coastal communities will have to deal with the spill for months or years. "If we have a three-month oil spill, we're talking about absolute devastation of the largest coastal fishery in the U.S.," Ralph Portier, an environmental science professor at Louisiana State University, told me.

Right now, dispersants are going a long way toward keeping the spill in check. "We've gotten some very excellent results showing that the oil dispersant mousse to a great extent degrades ... if we have a finite event," Portier said.

But it's hard to predict the long-term impact, especially if the end of the oil leak is not yet in sight. How will all those dispersants affect the Gulf's ecosystems in general and the fisheries in particular? Will blobs of degraded oil start washing up in Texas? Or in Florida?

"I guess our biggest concern is, we may have to redefine what an oil spill is," Portier said. "We may have to redefine what a catastrophe is. What if we have globules of oil that stay in the water column and continue to come ashore month after month after month?"

The dynamics behind the response to this oil spill are nothing like the dynamics that dictated the response to the Exxon Valdez oil spill more than 20 years ago. Back then, the massive spill was over and oil was washing ashore even before dispersants could have been flown up to Alaska. Today, the tools are in place to battle the spill. But for how long?

"If you visit the lower parishes, you'll see that people are in hurricane mode," Portier said. "It's the meteorologists who are telling the people where the oil spill is, just like it's the meteorologists who tell them where the storm is. There's a sense of urgency about ths. There's a sense of being tough about it. But it is kind of defeating not knowing when the end is going to be."

Source : msnbc