Monday, May 3, 2010

Oil Spill: Here's the Inside Scoop

The Gulf oil spill is much worse than originally believed.

As the Christian Science Monitor writes:

It's now likely that the actual amount of the oil spill dwarfs the Coast Guard's figure of 5,000 barrels, or 210,000 gallons, a day.

Independent scientists estimate that the renegade wellhead at the bottom of the Gulf could be spewing up to 25,000 barrels a day. If chokeholds on the riser pipe break down further, up to 50,000 barrels a day could be released, according to a National Oceanic and Atmospheric Administration memo obtained by the Mobile, Ala., Press-Register.

CNN quotes the lead government official responding to the spill - the commandant of the Coast Guard, Admiral Thad Allen - as stating:
If we lost a total well head, it could be 100,000 barrels or more a day.
Indeed, an environmental document filed by the company running the oil drilling rig - BP - estimates the maximum as 162,000 barrels a day:
In an exploration plan and environmental impact analysis filed with the federal government in February 2009, BP said it had the capability to handle a “worst-case scenario” at the Deepwater Horizon site, which the document described as a leak of 162,000 barrels per day from an uncontrolled blowout — 6.8 million gallons each day.
Best-Case Scenario

BP is trying to perform a difficult task of capping the leak by using robotic submarines to trigger a "blowout preventer" 5,000 feet below the surface of the ocean. Here's a photo of the robot trying to activate the switch on April 22nd:

(courtesy of the US Coast Guard)

If successful, the leak could be stopped any day. Everyone is rooting for the engineers, so that they may successfully cap the leak.

Already, however, the spill is worse than the Exxon Valdez, and will cause enormous and very costly destruction to the shrimping, fishing and tourism industries along the Gulf Coast of Louisiana and Florida. It will be years before good estimates on the number of dead fish, turtles, birds and other animals can be made.

The Backup Plan

If the blowout preventer can't be triggered, the backup plan is to drill another well to relieve pressure from the leaking well.

Here's a drawing prepared by BP showing the plan (the drilling rig on the left will take months to drill down and relieve pressure from the leaking rig):


Here's a graphic from the Times-Picayune showing the same thing (and accurately showing that there are currently 3 leaking oil plumes):

BP will also attempt to drop concrete and metal "cages" over the leak sites, to try to buy time by collecting oil in the cages, and then draining oil away in a safer manner. In addition, BP is using chemical disperants to try to break up the oil plumes before they rise to the surface (the dispersants are highly toxic).

Worst-Case Scenario

As the Associated Press notes:
Experts warned that an uncontrolled gusher could create a nightmare scenario if the Gulf Stream carries it toward the Atlantic.
This would, in fact, be very bad, as it would carry oil far up the Eastern seaboard.

Specifically, as the red arrows at the left of the following drawing show, the Gulf Stream runs from Florida up the Eastern Coast of the United States:


[Click here for full image.]

In a worst-case scenario - if the oil leak continued for a very long period of time - the oil could conceivably be carried from the Gulf Stream into world-wide ocean currents (see drawing above).

I do not believe this will happen. Even with the staggering quantity of oil being released, I don't think it's enough to make its way into other ocean currents. I think that either engineers will figure out how to cap the leak, or the oil deposits will simply run out.

Changing the Climate

There is an even more dramatic - but even less likely - scenario.

Specifically, global warming activists have warned for years that warming could cause the "great conveyor belt" of warm ocean water to shut down. They say that such a shut down could - in turn - cause the climate to abruptly change, and a new ice age to begin. (This essay neither tries to endorse or refute global warming or global cooling in general: I am focusing solely on the oil spill.)

The drawing above shows the worldwide "great conveyer belt" of ocean currents, which are largely driven by the interaction of normal ocean water with colder and saltier ocean currents.

Conceivably - if the oil spill continued for years - the greater thickness or "viscosity" of the oil in comparison to ocean water, or the different ability of oil and seawater to hold warmth (called "specific heat"), could interfere with the normal temperature and salinity processes which drive the ocean currents, and thus shut down the ocean currents and change the world's climate.

However, while this is an interesting theory (and could make for a good novel or movie), it simply will not happen.

Why not?

Because there simply is not enough oil in the leaking oil pocket to interfere with global ocean currents. And even if this turns out to be a much bigger oil pocket than geologists predict, some smart engineer will figure out how to cap the leak well before any doomsday scenario could possibly happen.

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