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BP Prepares Complex "Top Kill" Bid To Plug Well
shmG excerpts from the International Business Times: "Government and BP officials are hopeful after extensive preparations, but are not guaranteeing that a complex attempt early this week to cap an uncontrolled underwater oil spill from a well in the Gulf of Mexico will be successful. The so-called 'top kill' procedure that oil major BP is tentatively scheduled to attempt on Tuesday involves plugging up the well by pumping thick 'drilling mud' and cement into it. While it had been attempted on above-ground wells, it has never been tried at the depths involved with this spill, nearly 5,000 feet below the surface."
Then you do what you know how to do and you do it correctly
You keep your batteries charged in the BOP.
You tighten ALL the fittings and TEST them.
You double check everything and write it down, check it again. Stop when you find out you've missed something.
You don't send the crew with the test equipment home before they even start.
You have adequate mitigation strategies and you deploy them correctly.
You ask yourself 'whatcouldpossiblygowrong' and you try to answer the question. You keep the suits well away from engineering decisions.
Just like most man made disasters, multiple fuckups had to happen before the Shit Hits the Fan. This one is just another example of hubris.
Faster! Faster! Faster would be better!
Although he used the term "reduce the risk". There is always risk but this procedure seems the most logical one so far for all I know about oil well drilling.
1) Research the formation pressure vs the burst strength of the casing. They are way too close for comfort. Statically they're technically OK, before you collapse a drilling rig on top of them and have a month long blowout scour them from the inside out. Bad Slashdot Analogy : Its like using a racing engine, after its been in a crash, to power a fire truck. Its not like the theoretical burst pressure limit of the casing is a factor of 100x the internal pressure... They're cutting it close, maybe too close.
2) Contemplate that the root cause of the blowout was a cement bond failure... And cement is crazy weak in tension. So hooking up ultra high pressure pumps to push down extra hard, is not exactly the ideal situation.
So, the relief well is about 1/3 of the way done. It'll work no problemo. Top kill has a modest chance of working, a modest chance of failing without damage, and a modest chance of splitting the casing wide open like a sausage on the grill.
So its a simple game theory exercise:
Solution 1 has a 100% success rate but takes three months. PR folks will vaporize themselves waiting.
Solution 2 has a, lets say, 1/3 chance of doing nothing, 1/3 chance of success, and 1/3 chance of splitting the casing like an overcooked bratwurst, thus increasing the oil squirt rate by a factor of maybe 3. So leak rate is going to zero, stay the same, or increase perhaps a factor of 3, all equally likely.
Meanwhile the longer you wait, the lower formation pressure/leak rate drops. While at the same time sandstone is scraping out the inside of the BOP and casing making the leak larger. And both effects are very non-linear. So, it starts out very slow, gets very big, and gradually declines.
Some supercomputer or whatever calculated the optimum solution is : Wait until the relief well is about 1/3 of the way there.
I have no idea if anyone in slashdot-land can replicate the game theory math that lead to that answer.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
The cleanup is always a fecking pain in the arse.
That is why you prevent it from happening in the first place... I also work in the oil and gas business and the whole pile of neglect in the current case pisses me off to no end.
Last week Statoil in Norway had a blowout situation at a rig and the first safety barrier failed. If this had been the system in the gulf of mexico we'd be fucked over here too.... BUT there was a -second- barrier which stopped the problem. They locked down the well and there was no spill.
It is causing all manner of hell for Statoil at the moment though... people are quite nervous ;)