New Estimates of Oil Leak Rate Stoke Widespread Hysteria
These new inflated media estimates of the leakage flow rates are having the desired rate of ramping up public concern -- in the cases of some online commenters, outright panic. Here are a few articles reporting the newer, higher leakage estimates:
According to the new estimates, the Deepwater Horizon marine spill has already eclipsed the Exxon Valdez disaster in volume of oil released, and may have even made the top ten list of all time marine spills.
But are these estimates credible? Are these huge new estimates compatible with what is seen on the surface of the Gulf? Do we see many times the environmental damage as was seen from the Exxon Valdez?
If the Deepwater Horizon gusher has been spewing 100,000 barrels a day for the past 24 days, it would have released 2.4 million barrels of hydrocarbon, or about 100 million gallons (roughly 300,000 tons).
The distribution of oil spilled on the sea surface occurs under the influence of gravitation forces. It is controlled by oil viscosity and the surface tension of water. Only ten minutes after a spill of 1 ton of oil, the oil can disperse over a radius of 50 m, forming a slick 10-mm thick. The slick gets thinner (less than 1 mm) as oil continues to spread, covering an area of up to 12 km2 [Ramade, 1978]. During the first several days after the spill, a considerable part of oil transforms into the gaseous phase. Besides volatile components, the slick rapidly loses water-soluble hydrocarbons. The rest - the more viscous fractions - slow down the slick spreading. _offshore-environmentSo if one ton of oil spreads to cover an area of 12 km2, 300,000 tons of oil would cover an area of
Of course much of the short chain hydrocarbons will have evaporated, and some of the oil has sunk beneath the surface. But dispersants tend to spread the remaining oil across a larger area, somewhat magnifying the apparent area of the slick. In other words, had as much oil been released as is claimed by the mechanical engineer, the astrophysicist, and the oceanographer, would it not be reasonable to assume that virtually the entire Gulf would be covered by now?
Here is the rub: a very large part of the hydrocarbon release is in the form of natural gas, which evaporates into the air straightaway. Without knowing the proportion of gas to oil fairly reliably, one cannot truly predict how much oil is being released by watching (or taking rough measurements of) the seafloor gusher. And the lighter the crude oil, the more quickly the short chain hydrocarbons will evaporate in the warm Gulf waters. So one must also have a good idea of the type of crude that is leaking.
Certainly a couple of oil soaked birds and several dozen rubbery oil clumps washed ashore does not come close to matching the devastation of the Exxon Valdez spill.
If the engineer and scientists being quoted by a ghoulish media were honest, they would admit that their estimations are too crude to be taken seriously. Certainly too crude to be used to drive a national hysteria. But the media is not picky, as long as it gets its story.
Regardless of the rate, the gusher needs to be stopped so that top-side cleanup can be definitively carried out.
BP (BP 46.51, -1.59, -3.31%) attempted to thread a smaller siphoning tube into a larger pipe gushing oil into the Gulf of Mexico early on Friday, according to a company spokesperson in London. It's BP's latest attempt to slow down the oil spill that began on April 22 after the Deepwater Horizon rig caught fire. The company used remote control robots on the sea floor a mile below the surface to move the 6-inch tube into the 21-inch riser pipe, according to a report from the Associated Press. The pipe could be in place on Friday. _MarketwatchThe "siphon tube" approach is not a real solution to the seafloor gusher. It will merely suck up a portion of the oil being spilled. But if it is successful, it may improve the chances of other supplementary seafloor oil recovery approaches. It is certainly an ultra-cautious approach on the part of BP.
Information about the causes of the disaster are slowly coming to light, and there will be plenty of time for judging the actions of those involved. But for now, whatever the rate and composition of oil leak -- it needs to be stopped.
Very little oil washed ashore to date
Louisiana re-opens large fishing area
Attempts to siphon oil flow from seafloor riser continues The "top hat" attempt to cap the main gusher at the BOP will wait until the weekend.
Even More: Times Picayune video update on oil spill:
|Oil pill video: Reporters give latest update|
Labels: Oil Spills