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Robert L. Cavnar

Robert L. Cavnar

Posted: July 11, 2010 09:25 AM

Explaining BP's Explanation: Next Effort to Stop Oil

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Yesterday, I watched Kent Wells' presentation to the press explaining the latest operation that the Coast Guard finally pushed them into starting today.  Wells did a good job, as always, explaining the specific operation, but avoided key questions about what all of us want to know: the flow rate, and what happened to the BOP (blowout preventer).  As we talked about earlier today, the Coast Guard insisted that BP use the present weather window to get what is now called the "capping stack", which is three ram blowout preventer cavities with hydraulically controlled flow valves between them.  I don't know yet what rams are in the cavities (those are the big white things sticking out the sides), but obviously they have at least one set of blind rams.  Here's a good illustration of the entire assembly:

BP Capping Stack .jpgAs you can see, the bottom spool of the assembly bolts up to the flex joint flange at the top of the BOP (blowout preventer).  In normal use, the flex joint actually allows the riser going up to the rig to move with ocean currents and is usually made with an elastomer.  Wells said that they used hydraulic jacks to straighten the flex joint so it would provide a level surface to mount the new stack.  I still don't understand why they don't remove the flex joint, or the entire LMRP, for that matter, rather than landing this 150 stack on top of the flex joint.  Remember, the EDS (emergency disconnect system) is on the bottom of the LMRP (lower marine riser package).  I'm assuming that have found some kind of damage in that portion of the BOP, but I wish someone would ask that question.  I'm not holding my breath.  Anyway, on the very bottom of the transition spool (3 in the picture), below the flange, is a piece of pipe cut at an angle.  This is called a muleshoe.  Muleshoes are commonly used in downhole work, making it easier to get over other pipe that may be in the hole that is damaged.  Remember, there are 2 pieces of drillpipe stuck in the BOP that we talked about yesterday, and they're actually going to tie those together to allow the muleshoe to get over both of them making it easier for the two flanges to meet up and seat. 

The stack lands on the latching collar the will then be looking up from the spool.  Once the flex hoses are connected to the production valves on the side of the stack, they're going to do shut-integrity tests.  I assume this means they will close one of the rams partially and take pressure readings to see if pressure in the well is down enough to just shut it in.  They declined to give any more detail on that question, too, so we'll just have to watch what happens.  Here's Well's video from yesterday:



This is good progress, but my question is, that why did this stack take 2 1/2 months to build?  In one of the presentations, they said that this was one of the first ideas they had.  If that's true, why didn't they just build the damn thing?  It looks like all standard Cameron components, and it doesn't take 10 weeks to weld up high pressure spools.  This all seems like too little, too late, but I guess we all know why that is.

More on The Daily Hurricane Energy page.

 
 
 

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