[cbush]

> Good description of what happened - from an interview....
>
>
> This well had been giving some problems all the way down and was a big
> discovery. Big pressure, 16ppg+ mud weight. They ran a long string of 7"
> production casing - not a liner, the confusion arising from the fact
> that all casing strings on a floating rig are run on drill pipe and
> hung off on the wellhead on the sea floor, like a "liner". They
> cemented this casing with lightweight cement containing nitrogen
> because they were having lost circulation in between the well kicking all the way down.
>
>
>
>
> The calculations and the execution of this kind of a cement job are
> complex, in order that you neither let the well flow from too little
> hydrostatic pressure nor break it down and lose the fluid and cement
> from too much hydrostatic. But you gotta believe BP had 8 or 10 of
> their best double and triple checking everything.
>
>
>
>
> On the outside of the top joint of casing is a seal assembly -
> "packoff" - that sets inside the subsea wellhead and seals. This was set and tested to
> 10,000 psi, OK. Remember they are doing all this from the surface 5,000
> feet away. The technology is fascinating, like going to the moon or
> fishing out the Russian sub, or killing all the fires in Kuwait in 14
> months instead of 5 years. We never have had an accident like this
> before so hubris, the folie d'grandeur, sort of takes over. BP were
> the leaders in all this stretching the envelope all over the world in deep water.
>
>
>
>
> This was the end of the well until testing was to begin at a later
> time, so a temporary "bridge plug" was run in on drill pipe to set
> somewhere near the top of the well below 5,000 ft. This is the second
> barrier, you always have to have 2, and the casing was the first one. It is not know if this was
> actually set or not. At the same time they took the 16+ ppg mud out of the
> riser and replaced it with sea water so that they could pull the
> riser, lay it down, and move off.
>
>
>
>
> When they did this, they of course took away all the hydrostatic on
> the well. But this was OK, normal, since the well was plugged both on
> the inside with the casing and on the outside with the tested packoff.
> But something turned loose all of a sudden, and the conventional
> wisdom would be the packoff on the outside of the casing.
>
>
>
>
> Gas and oil rushed up the riser; there was little wind, and a gas
> cloud got all over the rig. When the main inductions of the engines
> got a whiff, they ran away and exploded. Blew them right off the rig.
> This set everything on fire. A similar explosion in the mud pit / mud
> pump room blew the mud pumps overboard. Another in the mud sack
> storage room, sited most unfortunately right next to the living
> quarters, took out all the interior walls where everyone was hanging out having - I am not making this up - a party to
> celebrate 7 years of accident free work on this rig. 7 BP bigwigs were
> there visiting from town.
>
>
>
>
> In this sense they were lucky that the only ones lost were the 9 rig
> crew on the rig floor and 2 mud engineers down on the pits. The
> furniture and walls trapped some and broke some bones but they all
> managed to get in the lifeboats with assistance from the others.
>
>
>
>
> The safety shut ins on the BOP were tripped but it is not clear why
> they did not work. This system has 4 way redundancy; 2 separate
> hydraulic systems and 2 separate electric systems should be able to
> operate any of the functions on the stack. They are tested every 14
> days, all of them. (there is also a stab on the stack so that an ROV
> can plug in and operate it, but now it is too late because things are damaged).
>
>
>
>
> The well is flowing through the BOP stack, probably around the outside
> of the 7" casing. As reported elsewhere, none of the "rams", those
> being the valves that are suppose to close around the drill pipe and /
> or shear it right in two and seal on the open hole, are sealing. Up
> the riser and out some holes in it where it is kinked. A little is
> coming out of the drill pipe too which is sticking out of the top of the riser and laid out on the
> ocean floor. The volumes as reported by the media are not correct but who
> knows exactly how much is coming?
>
>
>
>
> 2 relief wells will be drilled but it will take at least 60 days to
> kill it that way. There is a "deep sea intervention vessel" on the
> way, I don't know if that means a submarine or not, one would think
> this is too deep for subs, and it will have special cutting tools to
> try to cut off the very bottom of the riser on top of the BOP. The
> area is remarkably free from debris. The rig "Enterprise" is standing
> by with another BOP stack and a special connector to set down on top of the original one and then close.
> You saw this sort of thing in Red Adair movies and in Kuwait, a new
> stack dangling from a crane is just dropped down on the well after all
> the junk is removed. But that is not 5,000 ft underwater.
>
>
>
>
> One unknown is if they get a new stack on it and close it, will the
> ***** broach around the outside of all the casing??
>
>
>
>
> In order for a disaster of this magnitude to happen, more than one
> thing has to go wrong, or fail. First, a ****ty cement job. The
> wellhead packoff / seal assembly, while designed to hold the pressure,
> is just a backup. And finally, the ability to close the well in with the BOP somehow went away.
>
>
>
>
> A bad deal for the industry, for sure. Forget about California and
> Florida. Normal operations in the Gulf will be overregulated like the N.
> Sea. And so on.