September 23, 2010

expert reaction to new research on the Gulf of Mexico oil spill, as published in Science

A new paper re-examined the size and impact of the Gulf of Mexico oil spill.

Dr Simon Boxall, National Oceanography Centre, University of Southampton, said:

“The paper by Crone and Tolstoy is one of the first to show an objective measure of the flow from the Gulf of Mexico spill and the techniques used are in the main sound. There has been criticism of BP, the US Coastguard and the rig operators for not issuing accurate measures of flow from the leaking well. The paper shows that such estimates are by no means straightforward and have taken some significant research to provide values. The paper doesn’t provide estimates for amounts collected but there does seem to be a growing convergence on c. 4 Million barrels from a number of independent sources such as this.

“There is still a fundamental question. Is it the size of the spill or the fate of the oil that science needs to focus on? Evidence is also clear, now that the well has been successfully capped, that whilst this may be the largest single marine spill of oil it has not proven to be the most destructive. The depth of the spill, ocean conditions and the methods of coastal protection all helped to avoid catastrophic impact. Such research methods have an important application in identifying spill rates in determining best practice during an incident, but post-spill it is the fate rather than volume of oil that still needs attention.”

Dr Martin Preston, Senior Lecturer in Marine Chemistry, University of Liverpool, said:

“Overview: “This paper uses video image processing techniques to estimate the flow rates of the Gulf of Mexico oil spill and provides the first independent evidence of the flow at the sea floor. The results are based on a limited period of observations but the authors conclude that in the early stages of the spill the flow rate was around 68000 barrels/day (0.12 cubic metres per second) and that the total size of the spill was about 4.4 million barrels or 700,000 cubic metres. This estimate which has around 20% uncertainly indicates that the total amount of oil spilled was about 10 times that lost by the Exxon Valdez and that low rates were around 10 times higher than initial estimates.”

Comment: “This gives us the first independent estimates of the flow rates of the oil at the sea floor both before and after the removal of the riser. Within the margins of uncertainty the estimate of the total amount of oil released is in good agreement with other estimates such as that produced by NOAA and will I am sure be used as part of the legal assessments of the financial penalties likely to be levied on BP.””

Simon Rickaby, Chair of the IMarEST Pollution and Salvage Special Interest Group, and Managing Director of Braemar Howells Ltd, said:

“There is no actual way of proving how much was actually released from the well hole one mile down, so their figures could just as well be wrong as right, only when BP was taking the product onto the tanker floating above was there a quantifiable amount recovered, and then it would have come aboard as a mixture of seawater, dispersant and crude oil, this crude oil would itself be a mixture of neat, emulsified and diluted (by the dispersant injected into the plume) oil, which itself was not the totality of what was coming out of the bore hole.

“The plume seen in the video which is used as a basis for the calculations will have gas, water, oil and dispersant in it, and with all these items or detractions from the net amount of crude oil coming up from the underground reservoir needing to be taken into account, I personally find it remarkable and fascinating that the scientists can feel so certain about their figures, but I am not in any position to doubt their calculations only to point out those items which would present difficulties and need to be overcome to be so certain.

“Having said that any new tool, method or procedure entered into the armoury of combating spills is to be welcomed, and this measurement technique when applied to other incidents will in time prove its accuracy and credibility for response management to utilise when making their strategic and tactical decisions in the future.

“It should be remembered, it is not the total amount of oil spilt that is the major consideration in a spill response, but rather the type of oil and the quantity that has the capability to impact on the environment under threat.

“This incident with the vast amount calculated to have been released may in time be shown not to be as damaging to the environment as significantly smaller spills in the qualities spilt such as the Exxon Valdez (USA), Prestige (Spain) and Erika (France) incidents.

“Ironically in time it may be seen that the actions of others rather than the quantity of oil that came out of the seabed, may have had a greater negative effect on holiday businesses and vacation visitors than any oil that landed on the resort beaches, in some cases no oil as yet has impacted in a locality yet the local holiday trade has been severely impacted following articles in the press.”

‘Magnitude of the 2010 Gulf of Mexico Oil Leak’, Crone & Tolstoy, published in Science at 7pm UK time Thursday 23 September.