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:
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:
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.