Monday, June 7, 2010

Deepwater Horizon - The amount of oil spilled

2010-6-7 0.2

This does not look so bad, does it? I mean compared to the Ixtoc disaster what did not do too much damage in the Gulf of Mexico (at least according to Wikipedia). But why can nobody go check so the world get´s a better idea what to deal with?

Wikipedia on the Deepwater Horizon oil spill states:
The exact spill flow rate is uncertain – in part because BP has refused to allow independent scientists to perform accurate measurements – and is a matter of ongoing debate.
"BP has resisted entreaties from scientists that they be allowed to use sophisticated instruments at the ocean floor that would give a far more accurate picture of how much oil is really gushing from the well.

“The answer is no to that,” a BP spokesman, Tom Mueller, said on Saturday. “We’re not going to take any extra efforts now to calculate flow there at this point. It’s not relevant to the response effort, and it might even detract from the response effort.” (NYT)"

So what do we know:

BP initially estimated that the wellhead was leaking 1,000 barrels (42,000 US gallons; 160,000 litres) a day.

On April 28, the National Oceanic and Atmospheric Administration estimated that the leak was likely 5,000 barrels (210,000 US gallons; 790,000 litres) a day.

Timothy Crone, an associate research scientist at the Lamont-Doherty Earth Observatory, estimated at least 50,000 barrels (2,100,000 US gallons; 7,900,000 litres) a day.

Eugene Chaing, a professor of astrophysics at the University of California, Berkeley, estimated the leak to be 20,000–100,000 barrels (840,000–4,200,000 US gallons; 3,200,000–16,000,000 litres) a day.

Steven Wereley, an associate professor at Purdue University used particle image velocimetry to initially arrive at a rate of 70,000 barrels (2,900,000 US gallons; 11,000,000 litres) per day, with a margin of error of 20 percent.

Wereley concluded the leak was likely considerably more than he initially estimated, after viewing the released footage of the leak, stating before Congress that the leak was likely 95,000 barrels (4,000,000 US gallons; 15,100,000 litres) a day.

On May 27, 2010 the government increased its official estimate to 12,000–19,000 barrels (500,000–800,000 US gallons; 1,900,000–3,000,000 litres) a day.

According to Ira Leifer, a member of the Flow Rate Technical Group, the group was only provided an approximately seven minute time segment of low-quality video selected by BP, which showed a lot of variability from very low to very high flows.

PBS NewsHour:
The New York Times reported that BP told members of Congress the rate could be much, much higher:

In a closed-door briefing for members of Congress, a senior BP executive conceded Tuesday that the ruptured oil well could conceivably spill as much as 60,000 barrels a day of oil, more than 10 times the estimate of the current flow.

A barrel of crude oil contains roughly 42 gallons. In a follow-up story, the Times talked to a BP spokesman for more on the estimate:

"The rate could go up to that," Mr. Suttles of BP said, when asked to verify a report in The Times. "It's not the situation we have at this moment, but it's not impossible."

That all looks a bit more than (dead) fishy to me, pardon the pun.

If we now compare the Wiki entries from both spills so far:
Ixtoc I - Volume 3,000,000 barrels; 480,000,000 litres total - Area 2,800 km2; 1,100 sq mi - Coastline impacted    261 km (162 mi)
Deepwater Horizon - up to 100,000 barrels; 4,200,000 US gallons; 16,000,000 litres per day - Area 6,500 to 24,000 km2;  2,500 to 9,100 sq mi

46 Days since the spill.
46 times up to 100,000 barrels makes up to 4,600,000 barrels spilled so far.
4,200,000 US gallons times 46 days makes up to 193 million US gallons so far. I think you have a slight error in your calculation. It looks we already surpassed the Ixtoc I volume. has an interesting graphic and states correctly:
Note: the extent of the Deepwater Horizon oil spill has not been well determined as of this writing.
But their comparison of the biggest oil spills is quite interesting

So according to to low estimates it is still the smallest from the big spills, but according to the scientists it already kicked the Ixtoc I from the third spot.

Now some estimates are made on the amount of spread seen on satellite images. What they can not take into account is:
On May 15, researchers from the University of Southern Mississippi, aboard the research vessel RV Pelican, identified oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles (16 km) long, 3 miles (4.8 km) wide and 300 feet (91 m) thick in spots.

6.7 (cubic kilometers) = 42.141.732.200 oil barrel if the plume was rectangular.
So the amount is much smaller but there are more than one plume and they had time to grow. 

The shallowest oil plume the group detected was at about 2,300 feet (700 m), while the deepest was near the seafloor at about 4,200 feet (1,300 m). Other researchers from the University of Georgia have found that the oil may occupy multiple layers. Wikipedia

Scientists are finding enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots. The discovery is fresh evidence that the leak from the broken undersea well could be substantially worse than estimates that the government and BP have given.
The plumes were discovered by scientists from several universities working aboard the research vessel Pelican, which sailed from Cocodrie, La., on May 3 and has gathered extensive samples and information about the disaster in the gulf.

more at the New York Times

So 13 days after the accident there were already enormous oil plumes in the deep waters why don´t we hear more about that?
What if these plumes find the way into the Gulf Stream and dispersing the oil slowly up the coast line?