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Is it true that blind shear rams have a 50% failure rate?
Posted on 6/24/10 at 2:19 pm
Posted on 6/24/10 at 2:19 pm
Anyone got any good info on this?
1
Posted on 6/24/10 at 2:58 pm to Decatur
The stats that have been reported on the rams indicate about a 50% failure rate. What is interesting throughout all of this is how so much of what has been told to the federal gov't and the public has changed as time goes by. Here are the transcripts... Deep Water Horizon hearings
Posted on 6/24/10 at 3:13 pm to PeaRidgeWatash
quote:
The stats that have been reported on the rams indicate about a 50% failure rate.
Ok - this is the only helpful part of your post. After that you pose a question you seem to know the answer to but instead of elaborating... You link us 500 pages of government paper-wasting written in legalese.
Posted on 6/24/10 at 3:20 pm to yurintroubl
quote:
Anyone got any good info on this?
Plenty of good info in there, but you gotta look for it. If you don't want to, then don't.
Posted on 6/24/10 at 4:27 pm to PeaRidgeWatash
quote:
Plenty of good info in there, but you gotta look for it. If you don't want to, then don't.
And if somebody from out of town asks you if you know where the nearest emergency room is... and you say YES... then you hand them a phone book... you're an *sshole.
Posted on 6/24/10 at 4:50 pm to yurintroubl
Found this:
.pdf
Does anyone know of any more current studies?
quote:
1 Executive Summary
This study was designed to answer the question “Can a given rig’s BOP equipment shear the pipe to be used in a given drilling program at the most demanding condition to be expected?” Briefly, this can only be demonstrated conclusively by testing. Seven of the 14 cases above opted not to test to confirm capabilities; another had insufficient data to draw a definitive conclusion. This is presented below as Graph 1.
Of the seven tested, five successfully sheared and sealed (71%) based on shop testing only. If operational considerations of the initial drilling program were accounted for, shearing success dropped to three of six(50%). Based on the results obtained, two of the rigs modified their equipment to enable shearing and sealing on the drill pipe for their program.
The increase in drillpipe sizing as well as improved metallurgies, while benefiting the industry in many respects, detrimentally affects the ability to shear pipe should this last means of securing a well be necessary. Adding to the above concern is the hydrostatic effect of shearing at depth that must be taken into account. Knowledge of the findings herein should help prudent operators and drilling contractors provide a safer workplace while protecting the environment. Herein we briefly explore the data points available from recent shear tests and graphically compare their results.
API Specification 16A requirements and procedures used for shear testing are reviewed. Meeting Spec 16A requirements does not by any means guarantee that a rig is operating in a prudent or safe manner. The pipe referred to in the spec is not representative of that used on the 5th generation rigs operating at this time. Additional factors to be considered for more realistic operating conditions should be better understood before a final recommendation can be established.
This limited data set from the latest generation of rigs paints a grim picture of the probability of success when utilizing this final tool in securing a well after a well control event. While modifications, such as boosters or increased control system pressure, are available, demonstrative evidence that the installed shear rams will shear is often lacking.
...
WEST is unaware of any regulatory requirements that state the obvious: that the BOP must be capable of shearing pipe planned for use in the current drilling program.
Education of those involved should result in higher safety of drilling operations. It appears that at least some of the rigs currently in operation have not considered critical issues necessary to ensure that their shear rams will shear the drillpipe and seal the wellbore.
Does anyone know of any more current studies?
This post was edited on 6/24/10 at 4:51 pm
Posted on 6/24/10 at 5:45 pm to Decatur
The report was done in 2002 and a lot of things have changed since then.
I know that there was an engineer that either works or worked for Transocean that had done some type of study more recently that had concerns with failures of BOP's. I will see if I can find a link.
I know that there was an engineer that either works or worked for Transocean that had done some type of study more recently that had concerns with failures of BOP's. I will see if I can find a link.
Posted on 6/24/10 at 5:49 pm to Decatur
quote:
Does anyone know of any more current studies?
I don't know what you are looking for exactly... but I would start by searching internationally for the same or similar piece of equipment manufactured by a company not chosen by BP... and seeing if they have any information available publicly... or if they determined more testing was required. It may be able to find info on those who aren't involved than those who are.
I'm getting the sneaking suspicion that you are going to find a distinct lack of research material in which all the specific components that could have been used at these depths were adequately tested for all contingencies... Seeing as R & D would cost more than trying to use existing technologies... at tremendous depth... while tapping into something the size, scope and particulars of which are not exactly known quantities.
FWIW - If you go back to the threads from the first couple of weeks after this board was created - There were some pretty good threads which consolidated "known technical data" from a variety of sources.
quote:
Decatur
Let me just tell you that while I often seem aloof... I know that you have spent a lot of time both here and with your boots on the ground trying to find more answers and attempting to help in any way you possibly can.
It can't be easy making headway with this forum as your primary (or secondary or whatever... I admit I don't know ya) source of info and direction... Whatever end you are trying to reach - I sure as hell hope ya find it and put it to good use.
Posted on 6/25/10 at 2:15 pm to yurintroubl
quote:
And if somebody from out of town asks you if you know where the nearest emergency room is... and you say YES... then you hand them a phone book... you're an *sshole.
You are right, because they might not have much time.
But in this case, you aren't going to an emergency room, you're sitting at a fricking computer. He's not an a-hole, your just lazy.
Posted on 6/25/10 at 2:57 pm to Decatur
there has been a great deal of research into shearing technology in recent years, most of it focused on shearing casing and not drill pipe.
but i would say the question is more complex that just "is there a 50% failure rate". this was a 15k psi BOP stack and was more than capable of shearing all of the drill pipe tubes that come w/ the rig (a rig comes w/ thousands of feet of drill pipe as part of its standard equipment). however, i'd say it's very unlikely there's any shear ram on the market that could shear a tool joint (the heavy, thick 12"-18" end piece of each joint of drill pipe that encompasses the threaded connection).
also, shear rams are typically designed to shear a drill string that is in tension. when you start cutting the pipe, the hanging weight beneath it will fall away and the string will begin pulling itself apart. trying to cut a string in compression is far more complex, as more material is fed into the rams as the cut is being made. it would be like trying to cut a board w/ a saw while pressing the cut together.
i have no data to link to, but i'd say that blind shear ram reliability is far higher than what's indicated in the title. specifically because there have been a large # of emergency situations over many decades where blind shear rams have been closed on subsea BOP stacks (like extreme weather blowing a rig off location).
but i would say the question is more complex that just "is there a 50% failure rate". this was a 15k psi BOP stack and was more than capable of shearing all of the drill pipe tubes that come w/ the rig (a rig comes w/ thousands of feet of drill pipe as part of its standard equipment). however, i'd say it's very unlikely there's any shear ram on the market that could shear a tool joint (the heavy, thick 12"-18" end piece of each joint of drill pipe that encompasses the threaded connection).
also, shear rams are typically designed to shear a drill string that is in tension. when you start cutting the pipe, the hanging weight beneath it will fall away and the string will begin pulling itself apart. trying to cut a string in compression is far more complex, as more material is fed into the rams as the cut is being made. it would be like trying to cut a board w/ a saw while pressing the cut together.
i have no data to link to, but i'd say that blind shear ram reliability is far higher than what's indicated in the title. specifically because there have been a large # of emergency situations over many decades where blind shear rams have been closed on subsea BOP stacks (like extreme weather blowing a rig off location).
Posted on 6/25/10 at 3:03 pm to the LSUSaint
quote:
He's not an a-hole, your just lazy
And your grammar is as poor as your ability to judge character.
FWIW - I wasn't the one looking for answers I said what I said because if there's one person on this board with the wherewithal to research his own answers - It's Decatur.
If you aren't too lazy yourself - why don't you check his post history...
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