The LMRP Cap is Next Step

Saturday, BP announced what TDH had concluded hours before, that the top kill was a failure.  It failed because they simply couldn’t build up enough back pressure in the BOP (blowout preventer) to force sufficient mud into the well to kill the flow.  Clearly, the partially closed rams in the BOP, and the crimped riser above aren’t restricting flow from the well as much as everyone had originally thought, and the “junk shot”, pumping bridging material into the well, didn’t help, either.  I had figured they would try another couple of days to get through the Memorial Day weekend, and was surprised by their sudden announcement of the failure on Saturday afternoon.  This was their only chance to kill the well short of the relief wells, the first of which won’t get to the blowout well until late July or early August.

The next step to contain the flow?  The LMRP cap, which is essentially a containment dome that fits over the riser, on top of the lower marine riser package which is the top component of the BOP.  Before they land the cap on top of the LMRP, they must cut the bent riser that is still attached.  It is familiar to you; its where you’ve seen all the plumes of oil and mud on BP’s live streaming video the last several days during the top kill.  The cut is not easy; here’s an illustration close-up provided by BP:

BP Riser Cut.jpg

This is a really good illustration, but it leaves out the complicating factor that I’m worried about, which is the drill pipe that is inside the riser.  When the well blew out, there was 5 1/2″ drillpipe in the hole with a 3 1/2″ tubing stinger below.  Since we’ve seen drill pipe in the wrecked riser, I can only assume that that it’s also stuck in the BOP, and I’m concerned that when the saw gets to it, it could jam the saw and break it.  Also, as soon as the cut starts, visibility will be obscured because oil will begin blowing out of the new opening, so it’s likely they’ll be working blind. 

The saw they use is essentially a band saw that clamps onto the LMRP flange and then cuts with a diamond encrusted wire.  Here’s a video illustration of a diamond saw working on the surface:

I expect this to be a really slow operation as they make this cut.  I also won’t be surprised if they break a few diamond wires while doing this because of the loose drillpipe on the inside.

Once the cut is made, the cap will be landed on the riser looking up and set with a compression seal that will hopefully keep much sea water from coming in and prevent the formation of hydrates that we’ve discussed before.  Here’s an illustration of the cap, also provided by BP:

BP LMRP Cap .jpg

I won’t give a probability of success here, but this is about the last chance they have to contain the flow.  If this doesn’t work, they’ll need to get the LMRP off and try to land another BOP, which will be a very difficult operation.

I’ll keep watching and keeping you up to date.


  1. Dan says

    I like the idea of cutting off the riser and drill pipe above the riser connector.
    What I can’t understand is that if the cut is made successfully, why can’t they go 1 step further.
    That would require the unlatching and removal of the riser connector above the BOP stack leaving the drill pipe stub looking up inside the profile that the connector latches onto. That profile would allow another BOP stack to be latched onto it. The question is, is that profile rated to 15,000 psi. If it is not, then the LMRC is the best alternative until the relief well is finished.
    Good luck to BP with the LMRC plan.

  2. bubbabobcat says

    Bob with the top kill failing, you had mentioned in a previous post that BP is continuing to pump “mud” down to displace some of the oil leaking out. Is the mud less toxic and more biodegradable than raw crude? Though it sounds natural and harmless, my understanding is that the mud is a mixture of manmade chemicals.
    Thanks for continuing to stay on top of this mess and providing us real “read between the lines” information, Bob!

  3. says

    This mud is generally benign, but does have trace elements of some chemicals and minerals that in concentration could be a health hazard. It’s primarily water and barite, a naturally occurring mineral that is used as a weighting agent. I would rather see the mud than the oil, but they can’t keep doing that and get the cap on, too.

  4. carguy says

    Is drillling at this depth just too dangerous???
    I have read several safety “changes” Bob would make before restoring deep well drilling. What do you experts think about that????
    Lastly, can anybody tell me just how much (%)of the oil will be rendered “harmless” by environmental factors and how much of it will actually BE an environmental problem???

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