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Outline of the LMRP Cap Procedure Intended to Contain the Undersea Flow

With the top kill procedure having failed, BP is moving on to its next attempt: the placement of a containment cap on the Lower Marine Riser Package (LMRP). (Earlier post.) The LMRP is the top half of the blowout preventer (BOP) stack. This procedure is not intended to stop the well from flowing; it is intended to capture the flow while other procedures to cap the well are underway. The basic procedure, as outlined by BP, is to:

  • Riserremoval
    Riser removal. Source: BP. Click to enlarge.
    First remove the damaged riser from the top of the BOP. A remote operated hydraulic shear will be used to make two initial cuts and then that section will be removed by crane. A diamond wire saw will then be placed to cut the pipe close to the LMRP and the final damaged piece of riser will be removed.

  • The LMRP Cap is designed to seal on top of the riser stub. The seal will decrease the potential of inflow of seawater as well as improve the efficiency of oil recovery. Lines carrying methanol also are connected to the device to help stop hydrate formation.

  • The device will be connected to a riser extending from the Discoverer Enterprise drillship.

Analysis and discussion of the LMRP cap attempt  is on The Oil Drum here.



It looks like they have the LMRP planned out properly. I understand that the riser is bent over from the top of the BOP & extends to the sea floor. The first cut using the shears will release most of the riser from the BOP, and will leave some to provide a counterweight for the second cut of the diamond wire cutter. The second cut needs to be clean to allow fitting of the cap; using shears would mangle the riser and potentially create more problems. If anyone has ever cut metal with a hacksaw, having weight or adding weight to the piece that will be cut off reduces friction on the blade, reduces the risk of binding, and increases the chance for a smooth clean cut. There will still be a risk of binding (and machinery seizing up) if the diamond wire cutter isn't perfectly level throughout the cut.


I think you mean " . . weight to [on] the piece that will be cut off [can cause] binding".

The diamond wire cutter is unlikely to bind - especially if any pinching that occurs is gradual.

So maybe that's why they don't want a lot of riser still attached.


This seems to be more oriented towards future (potential) oil recovery than stopping the spill quickly. It would be ideal to recover 100% of the oil and gas while stopping leaks. That's probably what BP is trying to do.


Actually TT as gravity pulls down on the remaining piece of riser (after the initial shear cut) and the diamond wire cutter starts cutting, the weight of the riser will help open the cut slightly to eliminate / reduce friction on the blade / wire, and allow for a faster cut with much less potential of binding. In the picture they show cables attached to the riser --- which is fine as long as there will be some slack while they are cutting off the riser from the BOP...if there is tension and they are pulling up on the riser while using the diamond wire cutter, there might be binding and another failed operation. Because the cutter is a "wire" it may not be as much of a problem as a hacksaw-type blade.


Here's a good youtube video with what I think the operation is going to look like (sort of) ...


This is risky, the tube could swing while cutting, the cut may not be right and the top may not fit properly nor fit at all. Now you have much more oil coming straight out.

The have the "top hat" on the bottom, but chose to use the tube method instead. If the tube only got 10%, but the "top hat" can get 40%, I would say that it is worth a try.

If you are going to do this method, you better have a plan B in case the cover does not work. If that is suspending the top hat containment over the top of the BOP, then fine. Inquiring minds want to know that you are not just making it up as you go along and then weeks later it is....oops.


They keep saying this is the first time an accident like this has happened this, in a sense, they are making it up as they go along....


My saying is No Plan, No Preparedness...NO Permit.


They keep saying this is the first time an accident like this has happened this, in a sense, they are making it up as they go along....

They kept saying that this would never happen in the first place, that the BOP was "foolproof" and that they had a plan(and equipment) in place if it did happen. They WERE just making it up as they went along.



The offshore drilling president...the spill in the gulf hasn't even been stopped and the Obama Administration is approving new offshore wells IN THE GULF OF MEXICO, off the coast of LOUISIANA for oil exploration!!! The Associated Press APNewsBreak: Feds approve new Gulf oil well off La Is that warped or what?


At least THAT well is in shallow water (it's only 115 feet below the ocean's surface) and a full 50 miles away from the wildlife refuge, Canada is letting Chevron drill a new deepwater well off NFL; "Chevron Canada said it has started drilling Canada's deepest offshore oil well, located in the North Atlantic.

The Stena Carron drill ship is sinking the well, known as Lona 0-55, to a water depth at 2,600m, which will establish a new record in Canada.

The drilling is situated in the largely unexplored Orphan Basin, which covers an area of 62,140 square miles and will take several months to complete.

The well is 1km deeper than the Macondo well that was being drilled by the Deepwater Horizon rig before it ruptured and sank in the Gulf of Mexico, gushing an estimated 210,000 gallons of crude per day.

In the wake of the Macondo oil rig explosion, Chevron said the primary focus is on ensuring safe and incident-free operations during drilling.

Chevron Canada has two drill ships that can drill relief wells for the Lona 0-55 prospect, which could slow spills by relieving pressure if the well suffers a blow-out.

Chevron Canada holds a 50% stake in the venture while the rest is owned by Shell Canada Energy, ExxonMobil Canada and Imperial Oil Resources Ventures."


Actually the new drilling off the coast of Louisiana should come as no surprize, Obama did say offshore drilling would have to continue. Just a day ago he said the United States could only pursue offshore drilling as a short-term solution to its energy needs and said U.S. dependence on fossil fuels threatened its security while putting the economy and the environment at risk.

The president has previously supported an expansion of offshore drilling as a way to garner Republican support for the energy bill.

"I understand that we can't end our dependence on fossil fuels overnight. That's why I supported a careful plan of offshore oil production as one part of our overall energy strategy," he said. "But we can pursue such production only if it's safe, and only if it's used as a short-term solution while we transition to a clean energy economy."

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