Sunday, May 30, 2010

Pipe up the Leaking Oil - The New LMRP-Cap Attempt to Succeed

It has been more than one month since BP (British Petroleum) and the U.S. Government started to attempt stopping the catastrophic oil leak at Gulf of Mexico. I have not paid much attention until yesterday when I heard that an estimated 20 million gallons of oil have already leaked out, and the latest attempt to "top kill" the leak failed.

In general, it is easier to channel out the flow than to plug the flow. I hope the new "flow channeling" attempt, using the Lower Marine Riser Package (LMRP) Cap Containment System, would work.

The idea (see the graph) is to connect the LMRP Cap to oil outlet of the Blowout Preventor (BOP), with the help of Remotely Operated Vehicles (ROVs). The oil would then be piped up to the waiting surface ship, approximately 5,000 ft above.

The cap (with the pipe on top) must be lined up with the BOP outlet, and be connected and sealed to it, all to be done inside the oil gusher under an extremely high ambient sea water pressure (above 2,000 pounds per squared inch) and dark, turbid environment. I visually estimate the gushing oil would have a flowing velocity of only about a foot per second. The relatively weak oil gushing velocity, alone, should not create a problem for the pipe lining up and connecting. The high ambient pressure would not be a huge inconvenience either as long as pressures inside and outside the cap (and the pipe) are maintained essentially the same.

The question is whether this new attempt would succeed. I think it would. Many lessons have been learned from the previous attempts, especially on formation of the gas hydrates (the ice crystals).

There is also a concern about whether the new attempt would make the matter worse if it were to fail. I do not think it would make it worse, at least not significantly. There are multiple openings (at least two large ones) along the collapsed riser pipe at this time. Cross section area of the sole opening to be cut at top of the BOP should not be much larger, if at all, than sum of the areas of multiple openings. Moreover, change in the head losses would have a minor effect, considering the oil pressure head available.

The oil leak and subsequent several failed attempts (thus far) to stop the leak, yet again, highlight the importance of disaster prevention, preparation, response, and emergency engineering measures.

Image credit: BP

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