# Blow Out Preventers



## Catchinem (Dec 19, 2008)

Make the oil companies stack at least 6 BOP's on each pipe in case the first one doesn't work. A fifth grader knows that.


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## cml5207 (Feb 18, 2010)

That is like telling some to where six seat belts. Great idea but not likely to happen.


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## Buckyt (Oct 1, 2007)

When I was in the army (US) they always taught us to have a pair and a spare of any importand parts, safety devices, etc. That was in 1964! Thers oil drillers should have built in redundencies ( a pair and a spare)for all safety devices.


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## Bill Me (Oct 5, 2007)

I am as pissed as hell at BP and at our lack of effectivegovernment oversight, but my understanding is the BOP is effectively a tripple redundant system in itself. Would be curious to know from the industry folk on the forum, but that was how they were explained to me yesterday.

Just want to say I have moved passed denial and am somewhere between anger and action.


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## xxxxxxkidsoncoffee (Apr 30, 2008)

There's more than one BOP, they're usually just referenced as a whole. Not sure what kind of stack they had on this one. They could've had any combination of blinds, shears, and pipe rams. The blinds just crush the pipe, the shears cut it, and the pipe rams form a seal around the pipe.


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## Chasin' Tales (Oct 2, 2007)

> *kidsoncoffee (02/05/2010)*There's more than one BOP, they're usually just referenced as a whole. Not sure what kind of stack they had on this one. They could've had any combination of blinds, shears, and pipe rams. The blinds just crush the pipe, the shears cut it, and the pipe rams form a seal around the pipe.


That's mostly correct. Blind rams aren't made to crush pipe (although they very much will!). They are made to blind off the wellbore.

There are redundancies in the BOP stack.

In this case the BOP stack is attached to one of the casing strings in the well and is sitting on the sea floor in 5000' of water. There is a riser that connects the BOP's to the drilling rig. The riser is basically a large central pipe with several other pipes on the outside along with flotation. The flotation is to make the riser neutrally bouyant. Some of the smaller pipes on the outside of the riser are what are used to function the BOP stack. 

There are two types of BOP's, annular & ram. 

The annular preventer, when closed, forms a seal around the outside of whatever tubular is being ran in the hole. It seals the annulus between the outside of the tubular and the casing. 

There are several types of ram preventers. All drilling stacks will have blind rams, shear rams, and pipe rams. Blind rams come together and seal off the wellbore completely. They can not be closed if there is pipe across the preventer. Shear rams will shear the pipe when closed. Pipe rams are similar to the annular preventer and seal off the outside of the pipe. Sometimes the blind and shear rams are combined into one blind/shear ram.










The choke and kill lines on the riser are used to circulate out a kick once the BOP's have been closed.

In any case, the BOP's are functioned hydraullically. MMS requires, at a minimum, BOP's to be functioned tested every 7 days and pressure tested every 14 days. 

Once a well is drilled, production tubing is ran. At this point, the BOP's are nippled down and a tree nippled up in it's place. Both the tree and production tubing have fail-safe valves that will automatically close durning a catostrophic event. Having a spill of any magnitude is much, much less likely at this point.


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## opus68 (Sep 28, 2007)

What is this additional safety valve that the news is saying wasn't installed because it was not required? They claim that other countries (Norway for example) require an additional safety valve but we do not. Sounds like there are already lots of safety valves. Could this one made a difference?


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## Oldsurfer (May 2, 2010)

Everybody will be looking to blame someone but in the end it was bound to happen. Nothing is failsafe and with over 4000 wells already in the Gulf it was just a matter of time until this happened. I doubt if this will have any impact on gasoline prices. Gas prices are only loosely based on supply and demand anyway and this well was not producing any oil anyway. It is a predictable tragedy and will happen again as long as we continue to drill offshore.


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## lastcast (Oct 12, 2007)

BP knew the BOP didn't work right.

http://www.kansascity.com/2010/04/30/1914996/us-report-found-failure-of-offshore.html

Skip


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## Chasin' Tales (Oct 2, 2007)

> *opus68 (02/05/2010)*What is this additional safety valve that the news is saying wasn't installed because it was not required? They claim that other countries (Norway for example) require an additional safety valve but we do not. Sounds like there are already lots of safety valves. Could this one made a difference?


It's the acoustic actuator that was mentioned above. From what I understand is that it's not an additional valve, rather just another way to actuate the BOP's that are already in place. Basically the acoustic acutator uses an acoustic signal from the surface to close the BOP's. 

In this case, the rig crew attempted to close the BOP's. Remote operated vehicles have also tried to close the BOP's. These attempts have obviously not been successful. Nothing suggests that an acoustic actuator would get the BOP's to function either.


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## P-cola_Native (Feb 5, 2008)

Now we know what a BOP is and how it works, and we also know that the one on DH failed. This is the same fail safe that is on all of the other rigs. So what possible conclusions can be drawn here...

It seems to me that drilling isn't 100% safe, no way is it possible. No matter what happens that damn well head can still release oil if something happens that makes the experts go, "I don't know, it shouldn't have happened."


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## xxxxxxkidsoncoffee (Apr 30, 2008)

> *Chasin' Tales (02/05/2010)*
> 
> 
> > *kidsoncoffee (02/05/2010)*There's more than one BOP, they're usually just referenced as a whole. Not sure what kind of stack they had on this one. They could've had any combination of blinds, shears, and pipe rams. The blinds just crush the pipe, the shears cut it, and the pipe rams form a seal around the pipe.
> ...


Sorry, I'm used to a snubbing unit. The blinds are made to seal the wellbore, but I've seen them used several times to crush the pipe and reduce the pressure so the annular can contain the gas and the valve can be stabbed.


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