Assuming a clear path through the BOP... ISTR seeing comments that there was another pipe inside the outer pipe at the time of the blow out and that the BOP may have partially operated.
Having something threaded through the BOP raises a question on how the BOP valves can close when it has something through it. Presumably the valves are suffciently strong and powerful enough just to slice through what ever is in the way?
The reading I've done on them in the last couple of weeks claims that they can, but clearly for whatever reason this one isn't able to close off, or they'd have done that ...
I think it is evidence of what the British like to call the "Special Relationship" between the USA and the UK.
The culprits couldn't possibly be American. As the whole world knows
- because we've watched the movies - Americans are always right.
Does anyone here know how the BOP is powered?
And soon to be dead.
It's the one's which aren't dead you need to be worried about... I'm glad we are not marine animals - some of that stuff that lives down there is just odd.
I wonder how the movie will run. I watched U 571 recently. I think the sequel will be called URA 1.
But why does nationalism lose track of the fact its just rich people who are at fault. It slips away so easily that the nationality is immaterial in such debacles, it's just a cliche' for misdirection.
I don't think you mean chimney effect. That is a matter of pressure differences. Also the differences in the densities of the liquids are relatively immaterial. The distance are considerable though, probably a cause of the problem or a significant part of it.
The currents caused by thermo haline chimneys are also significant.
It's a mixture of oil and water at very high pressures and low temperatures that causes clathrates. But the chemical is stable and a non pollutant so maybe leaving the stuff alone is the better option.
Given time, slight oil leaks at that depth would fund reasonable ecosystems. I'm not advocating evolution of course. Magic accidents don't ever work for the greater good. Leave that to Marvel Comics and BBC Natural History programmes.
It's just a failsafe device God fitted into an environment that he was about to hand over to a bunch of losers.
I'm not sure how many systems it has, but a key back-up system was powered by a battery which apparently failed.
Odd creatures don't worry me (with the exception of my neighbour).
Not quite sure what causes the draw on a chimney it's more than just warmer air inside rising, hasn't the passage of air over the top got a lot to do with it as well. Note warm air rises because it's less dense.
Not so sure. You have 5,000' of water giving something over 2,000psi at the bottom of a tube filled with oil/gas/water whose weight can only provide say 1,500psi at the bottom. Therefore you have 500psi shoving the oil/gas up the tube, provided the tube is open at the bottom. If you can seal it from the oceain it's only (ha!) the overpressure from depth that is pushing the column of oil/gas upwards.
The "top kill" was sort of opposite of this, fill the tube with something heavier that what is rising and it'll be forced down, at some point the column of heavier stuff will also overcome the pressure shoving upwards. At least in theory...
Hydraulics.
There's a seried of big accumulators which store pressure. Control lines ( either hydraulic or electrical ) from surface controll the dumping of the pressure into the rams.
A BOP has several different sets of rams in it, for use in different situations.
1) Blind rams. These are square-faced, and simply close against each other, when there's nothing in the way.2) Pipe rams. These have a semi-circular cut-out profile on each side, and are designed to seal around drill-pipe.
3) Shear rams. These have a cutting blade, and are a last-resort deal and are designed to cut through drill-pipe which may be in the way.Shear rams cannot cut through *anything*, though. It seems there may be heavyweight pipe or Drill Collars or somesuch across the rams, preventing them closing.
These must be impressive objects. What is pressurized? Air?
Hydraulic fluid, compressed against a Nitrogen cushion. Normal working pressures in the range 3000 - 6000 psi. Stacks of 10 or 15 gallon bottles.
Have a look at the pictures on this PDF for an idea of scale:
Thanks Ron, all makes sense. You don't really want to cut a drill pipe and have it drop down the hole unless there is no other option... I'd have thought the shear rams would have been able to cut through a collar though. Assuming a "collar" is where two bits of drill pipe screw together. Sods Laws insists that if you need to use the shear ram there *will* be a collar located there.
Looking at the live cameras the spillage has much reduced in the last
24hrs and was noticeably reduced the day before.
Not quite. The word 'collar' has different meanings.
It *can* mean the joint between 2 bits of pipe, usually casing ( which has a male thread both ends, and a casing collar is joining piece with a box-end either side.
But in the context of a drill string, it means something quite different.
Drill pipe is designed to be in tension. You can't push down on it. The hoist arrangement in the derrick must always be supporting the full weight of the drill-pipe, so that none of it is in compression, or it will buckle and may fail.
The Weight On Bit ( WOB ) required to break rock is provided by very heavy sections of pipe, immediately above the bit, called drill collars. These are still tubulars, but with a massive wall thickness.
Imagine a black-and-decker suspended on a bungee cord, with some lead weights to push it down!
These are part of the Bottom Hole Assembly ( BHA ), which consists of the bit, the drill collars, stabilisers, LWD /MWD instruments, and heavyweight drill-pipe. Then we have standard drill-pipe back to surface.
These BHA components may not be shearable.
I've not tuned-in to the ROV cameras for a while, but there seems to be plenty going on down there for the fitting of the replacement cap
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because Obama's dad was imprisoned by the British during the Mau-mau rising?
Robert
Or the going over our GM nutters gave Monsanto a few years back.
regards
And the perfect antidote to the world cup final. B-)
Just watched them mount the transition spool onto the top of the BOP. A nice clean insertion but then it stopped with about 2" between the flanges at about 2025 BST. 20 mins of looking closely at the gap and some checking the wire lines tension and I think they picked it back up a few inches and dropped it to get the flanges to meet. They are now (2110 BST) removing the bolt keepers and doing them up.
Not much of a power pickup at half time.
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