BP Deepwater Horizon – Phase 3 Riser Removal and Capping of BOP

Posted: May 31st, 2010 by: h-2

Well, here’s two graphics that show the next step. You can get high resolution versions by clicking on the images. Source: BP riser cut/cap info page. (Update: see comments for updated progress on the shearing operation, which failed on the first attempt).

You can also watch the BP LMRP capping project video that was just released. Personally, that guy who presents makes me sort of ill to watch, but you can get a sense of the project, with liberal doses of Corporate spin to reduce the impression of disaster (note especially the image of the oil coming out of the BOP stack, it’s a light gray haze, instead of an angry black cloud, which is what it really looks like).

Step 1: cut the pipes:

Step 2: lower the cover/LMRP cap onto the cleared BOP top:

And there you have it. Slice the main part of the drilling riser tube away from the BOP unit (blowout protector) with giant hydraulic clippers, then carefully slice the riser/drill pipe at the BOP with a diamond band saw.

That will in theory provide a reasonably flat surface to fit the device they will then lower down onto the top of the BOP.

The New York times has this piece today,
BP Tries Again to Divert Oil Leak With Dome

“This is a containment operation that is more straightforward,” Robert Dudley, BP’s managing director, told CNN on Sunday morning. He said containing most of the escaping oil until a relief well could be drilled was “not a bad outcome compared to where we are today.”

Mr. Dudley and other senior company officials have said they do not expect that the operation, even if it fails, will worsen the flow of oil significantly. BP officials said a week ago that they estimated that a 10 to 15 percent increase was possible until the cap is firmly in place.

But a technician working on the project expressed concerns that engineers cannot be sure how much more oil might escape if the operation fails.

“We’re all concerned about it,” said the technician, who spoke on condition of remaining unnamed because he is not authorized to speak publicly for the company. “We simply do not have the data about the internal geometry of the blowout preventer” to determine what volume of oil is being contained by the damaged blowout preventer and any damaged equipment or debris inside it.

During the previous attempt to install a containment dome, icy water rushed into the box and filled it with natural gas hydrates. Ice crystals formed from water and natural gas under the high pressure a mile down. There was no room left for escaping oil in the dome, which also became buoyant and rose to the surface.

This time, tubes will deliver heated sea water and antifreeze to the vessel. But the technician said that the formation of hydrates was still possible.

4 Responses to “BP Deepwater Horizon – Phase 3 Riser Removal and Capping of BOP”

  1. h-2 says:

    Quick update on this one:

    12:37 CDT The ROV moves to the side of the shear that is away from the BOP as the shear continues applying force to the riser. No oil and gas are erupting from the riser. The shear released its grip and then reapplied it just before the ROV changed position.

    12:40 CDT The ROV appears to be making a 360 degree inspection of the riser pinched by the shear.

    12:42 CDT The ROV has returned to its original monitoring position near the BOP and slightly below the shear.

    12:46 CDT The shear as opened again. Nothing visible erupting from the riser. oildrum comment

    1:47 EDT Update: The giant shears have been removed. It appears to have been a total failure. theoildrum comment

    Not confirmed yet, still catching up a bit on today’s progress.

    In other words, as of that time the huge sheers failed to cut the riser pipe. This doesn’t really make the BP engineers look that great, I mean, they know what the pipe is, and what it takes to cut it, so one has to wonder a bit here about what’s going on. They tried a few different spots along the riser, I assume because maybe there were pipe joints that would be harder to sheer, but no joy, it just dented the riser pipe casing. Sigh. Well, they are trying, and it’s 5000 feet down, so I would imagine a lot of these things are just guesses to see if they will work, that’s how tech work is too, you never really know until you dig into the project what will work and what won’t, though you can have a good idea, but when it’s very complicated, which this project is at this point, you know less and less, and learn more and more.

    Ah, a bit more:

    shelburn on June 1, 2010 – 3:11pm Permalink | Subthread | Parent | Parent subthread | Comments top

    About the shear and possible failure thereof:

    I have said this before – be very careful of interpretation from an ROV video. The lens are very wide angle and the distortion is such that a 90 deg corner at the center of the picture can easily appear to be 120 degrees. Also the shears do not have to be perfectly at right angles.

    I don’t think the anvil position is very significant. When sheared the riser is either going to try to go down because the section on the seabed was helping hold it up, or it will try to go up as the weight of the the cut portion is released and it will probably also jump to one side or another. There is rigging to a crane on the surface that will keep it from dropping very far.

    There are numerous reasons for hydraulic failure – kinked hose, stuck valve, non-operating valve, blocked non-return, etc. I highly expect it is something like that.

    A rigging problem is possible but as the shears were in place unlikely. An ROV problem, unless directly related to the shear is unlikely as they would have just used another ROV, not removed the shear.

    Some other posts suggest engineering errors in designing the hydraulics to be capable of shearing the riser. I seriously doubt that. The material properties of the riser, the drill pipe and all the other lines are known and hydraulics is not exactly rocket science. Any number of highly capable engineers will have checked, rechecked and reviewed the calculations and capable mechanics will have built the shear.

    Mechanical failure somewhere in the hydraulic system is most likely.

  2. h-2 says:

    And more, shear on the way back down:

    nerd on June 1, 2010 – 6:52pm Permalink | Subthread | Parent | Parent subthread | Comments top

    The shear is back on its way down, so it looks as if they were clearing off a section of riser, so that the shear could ‘just’ cut the main Riser pipe. Seeing how little impact the shear made the first time. I wonder if there was some other problem, such as low hydraulic pressure or some such

    tollertwins on June 1, 2010 – 6:48pm Permalink | Subthread | Comments top

    Section of pipe now clear of all ancillary tubing…shears coming back in view!

    BlueTwilight on June 1, 2010 – 9:45pm Permalink | Subthread | Comments top

    18:23 CDT. The shear has been dangling over the riser for the last 30 minutes. The claw was closed and then opened.

    18:34 CDT. Finally the shear is being positioned around the riser.

    18:36 CDT. The ROV is maneuvering to the side of the shear away from the BOP. The shear is positioned very close to the end away from the BOP where the smaller pipes were cut off.

    18:38 CDT. The ROV has returned to the BOP side of the shear.

    18:47 CDT. The ROV continues moving around inspecting the shear whose jaw is not perpendicular to the length of the riser. Maybe BP is going to cut it diagonally. The ROV is on the side of the jaw with the blade. The other side is blunt.

    18:56 CDT. The jaw of the shear clamps around the riser.

    19:13 CDT. The shear is crushing the riser and some dark material is drifting up from the far side of the jaw.

    19:14 CDT Dark material is ejecting from the near side of the riser blocking the view of the shear. The material is shooting downward with force, expanding and then rising into a plume.

    19:17 CDT. The part of the riser away from the BOP is at an angle to the other side and has apparently severed off. A big black cloud completely envelopes the shear.

    19:19 CDT. The cloud clears on this side making the shear visible again.

    19:26 CDT. The shear continues to clamp down. The left side of the shear is mostly shrouded in a black cloud

    19:29 CDT. The shear releases its grip, slides along the riser in the direction of the BOP and rises up clearing the riser. The dark cloud of ejected material obscures the view of the apparently disconnected part of the riser.

    19:32 CDT. The ROV shows a view of the BOP along the riser. Material is still being ejected from the holes at the kink above the BOP.

    Looks like success.

    19:39 CDT. The ROV is moving toward the diamond wire saw attached to the top of the BOP.

  3. h-1 says:

    And finally, the diamond saw failed but they used the snippers to cut the top riser / drill string and are now ready to go ahead with the LMRP installation.

    The diamond saw got stuck so they had to give up on getting a super clean cut.