BP has discontinued their calculations on the amount of oil exiting the well; they have handed this responsibility to the US government. Just yesterday, this taskforce announced that approximately 25,000 to 30,000 barrels of oil are flowing into the Gulf per day. On May 27, BP had estimated that anywhere between 12,000 and 19,000 barrels of oil were exiting the well per day. A month before that, the estimate was 5,000 barrels per day. The first estimate, given several days after the start of the spill, was a “mere” 1,000 barrels per day. 50 days after the oil spill, one could only hope that this number would start to decrease… not increase…

By studying the estimates given by BP, you will see that an almost perfectly (positive) linear relationship exists between the time that has elapsed and the magnitude of the flowrate. In fact, a 95% correlation exists.*

Last week, a containment cap was placed on the well to control the amount of oil exiting into the Gulf. The cap can capture 11,000 barrels per day. However, a large amount of oil is still escaping. The containment cap was designed to funnel the oil to a ship on the surface. Another containment system, which uses the pipes of a previously failed attempt to control the leak, directs more oil to an extra vessel. An additional method is supposed to be installed by the end of this month. This method is expected to withstand hurricane conditions.

The containment cap was lowered onto the failed blowout prevented (BOP) valve system on the seabed. The cap was placed on the lower marine riser package (LMRP) section of the BOP. On June 1, the damaged pipe which removes oil from the well, known as the riser, was cut near where it reaches the seabed. Undersea robots were used to cut through the riser close to the LMRP. After the riser was removed, the cap was lowered onto the LMRP, enabling the leaking oil to be funneled to the ship on the surface.

Schematic of the containment cap on the LMRP

It is difficult to determine whether the cap is effectively working, mainly due to the lack of consensus regarding the magnitude of the spill. Currently, the total volume of oil that has escaped the well has been estimated to be anywhere between 20 million to 45 million gallons. The flowrate of oil leaving the well has fluctuated greatly and rapidly evolved – from an initial estimate of 1,000 barrels/day to a present estimate of 27,500 barrels/day.

Officials warned BP that cutting the riser may worsen the leak by 20%. Ira Leifer, an expert part of the government taskforce to determine the flowrate, believes that installing the containment cap has made the leak worse. Leifer claimed that the pipe is fluxing more than it previously did. BP has not made any claims as to whether the leak has worsened – they have merely claimed that their engineers are working to make the containment cap as efficient as possible.

Let’s say that cutting the riser did worsen the leak by 20%. The latest estimate by BP (approximately 27, 500 barrels/day) was released after the riser was cut. So according to officials, the exit rate of oil would have been approximately 4,580 barrels/day less, if the riser was not removed. However, the containment cap is projected to capture 11,000 barrels/day. Thus, the additional oil spewing out of the well from installing the containment cap is an additional sacrifice the Gulf of Mexico has to take.

However, we do not know if cutting the riser actually worsened the leak – just like the exit flowrate, there is no consensus on this matter either. BP has not made any statements on the efficacy of the cap. Some officials, including Leifer, believe that the cap worsened the spill by significantly more than 20%. The one thing that is certain about this oil spill is the amount of uncertainty it has produced. Oh, and of course, the amount of damage that it has caused, and will continue to cause.

Oil Pools near Barataria Bay on the Louisiana Coast

A permanent solution to the leak must be discovered soon. BP is digging two relief wells by the end of August. BP hopes that these wells will provide a permanent solution to the oil spill; again, it is uncertain whether they will be truly successful.

The spill has killed 11 humans; many birds and marine animals have either been severely injured or killed. A third of the federal waters of the Gulf remain closed to fishing. Admiral Thad W. Allen of the Coast Guard described the oil spill as “an insidious enemy that’s attacking our shores.” The oil spill has been called the nation’s worst environmental disaster. President Obama has claimed that if Tony Hayward, the chief executive of BP, worked for him, Hayward would have been fired for his poor handling of the oil spill.

* Calculated by plotting the estimated flowrate versus the number of days elapsed since the spill started. The estimates released on May 27^th and June 10^th were given as ranges. For the purpose of obtaining a correlation, the values were averaged to obtain an approximate flowrate of 15,500 barrels/day and 27,500 barrels/day respectively.

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