Tag Archives: BP

Needlessly invoking clathrates. BP’s underwater ice machine.

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In the news reporting on the BP oil spill, there is talk of methane/water forming a special ice composition that defeated the previous attempt to channel oil to the surface.  I think folks are referring to clathrate formation. This ice blocked the flow of petroleum from the concrete structure that was lowered over the well head.

But, here is the deal. Wouldn’t you expect cooling of a compressed gas as it exits the well pipe and into the sea water? Isn’t this just an example of the Joule-Thompson effect?  As the natural gas component of the petroleum discharge exits the pipe, it is going to expand somewhat, even at a one mile depth, and cool the surrounding water. If this occurs in unconfined, open water, the jet of petroleum will entrain water in the flow and be warmed by the continuous flow of heat from the water.

But, if the gas/oil mixture of petroleum is ejected in a confined space that interferes with heat transfer, then one would expect the expansion cooling of the gas phase to predominate and cool the water in the confining space, possibly to the freezing point. Clathrates may be formed, but the simplest explanation is from good old thermodynamics.

BP oil spill. What are the merits of using dispersants?

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BP Oil Spill Image, May 4, 2010 (NASA Earth Observatory)

Oil Spill near Mississippi delta. Vegetation, red; Oil, silver. MA 24, 2010. (NASA Earth Observatory photo)

Eventually, BP will find a way to block the discharge of petroleum into the Gulf of Mexico.  And, eventually, the effectiveness of how the relevant parties responded to the incident will be analyzed and findings posted.

I hope that some effort will be put into an analysis of the merits of using dispersants in general and Corexit in particular. What sparks my comment is the finding that considerable subsurface petroleum has been found. This material is evidently close to neutral buoyancy and is drifting with the currents.

Question 1: Is there a connection between the dispersant use and the presence of this subsurface body of petroleum?  

Question 2: What is the desired outcome of dispersant use?  Where did the planners think the petroleum would go?

Question 3: Is there any advantage in encouraging petroleum to remain below the surface, if that is even possible?

At some point, a decision was made to use dispersants on this massive discharge. Is there a scientifically supported rationale for this, or was it palliative treatment intended to mask the surface effects of the release?