i didn’t remember seeing it when the big scissor sniped the riser when the band saw didnt work or when they put the top hat on.
[QUOTE=View 2 a ?;37567]What looks like a pipe sticking up can be seen from skandi rov1, where that come from?[/QUOTE]
If it’s the one I’m looking at, the video feeds aren’t named where I’m viewing them, it’s either pipe or a rod that serves as a handle to the dispersant dispenser.
looked like eroded dp to me,if the well is making sand, i’d be willing 2 bet on, whatever part of the stack that was holding it lost some of it’s grip. i could only see it in between gushes of oil and could see the disperant rod clearly on the outer edges.
[QUOTE=View 2 a ?;37572]looked like eroded dp to me,if the well is making sand, i’d be willing 2 bet on, whatever part of the stack that was holding it lost some of it’s grip. i could only see it in between gushes of oil and could see the disperant rod clearly on the outer edges.[/QUOTE]
Could it be that some of the riser that was left after the cut has been eroded away - and what you see through the short side now is the DP that was left after the shearing ?
I sure hope this is ok to do. Here is the link to the thread on Drilling Club post 1245 by grunterhunter. Appears to be a darn good analysis and write up that parallels what a gent on this board was sharing with me. Again, hope not violating protocol by long quote.
This is only my opinion (grunterhunter), I can not prove anyof it, but I think it will come to light.
Everyone is saying they can not figure out what cause the Rig to Explode so quickly, the loss of 11 souls, the failure of the BOP. It is not that hard to figure out. I have been in the drilling business for almost 21 years. I could not get exact information as to casing trengths and all the data that would have been helpful to come up with perfect calculations, but there is only one circumstance and scenario that can cause this to happen in my opinion.
The information has slowly passed across the internet as to all the well data: mud weights, depths etc. I have had to piece and
separate the facts from the fiction to come to my conclusions.
I see where they are holding the Captain responsible for the largest oil spill in History and saying anyone on that rig could have simply called a time out. I will assure you that that Captain had nothing to do with this spill, nor could he have prevented it. Nor could have the 11 men that died or the men that lived through a fiery hell.
In my opinion using my knowledge and experience no one could have stopped what appears to me was the makings of a disaster. They built the 20 hour bomb accidentally and it would have been impossible for anyone to detect what was going on until it exploded.
I believe they made a grave mistake in their design and then continued to make others after it started going wrong.
The secret to this I am sure is when they decided to pump Nitrogen cement into an abnormally pressured deep-water well. They should have never done this is my opinion. The last thing you would ever want; is to end up with gas behind the casing string in a Deep-water well. You do not want gas behind any casing string anywhere. It is different on a land rig or a surface BOP where you can actually let the nitrogen surface as it breaks out of the cement. It is not contained and even if you install the hanger seal you can still monitor the pressure behind the casing through a well head wing valve. But if you do this on a Deep-water well as soon as they installed the pack off in the casing hanger at 5000 ft. it was the same as lighting the 20 hour fuse. The gas continues to migrate and there is no place to monitor it or to bleed it off. The pressure just keeps building.
It is one thing to positively design a well and use all the data and information from books and manufacturers design criteria considering known or expected pressures, but wells also need “WHAT IF CALCULATIONS” I call it (negative or what if) Engineering.
Three “WHAT IF” calculations should have been made and apparently they were not.
- What if the Nitrogen migrates up the annulus behind the casing after the seal assembly is set?
- What if the cement job fails altogether and the shoe is not encapsulated and the formation is not isolated either?
- What if both of these occurred?
I believe these things happened on the HORIZON and that is what has caused this disaster.
Gas has to expand somewhere to relieve the pressure of the bubble as it migrates to surface or to shallower depths. (MIND YOU THERE SHOULD NEVER BE ANY GAS BEHIND CASING IF ALL IS DONE CORRECTLY).
One barrel of gas from the bottom of this well will increase in size by approx. 884 times when it reaches the surface. This is 884 barrels or 37,142 gallons from the original 1 barrel of gas which entered the well bore at 18,000 feet. Gas expands based on Boyle’s Law.
P1 X V1 = P2 X V2.
I personally believe the nitrogen cement job started the events although it seems other bad practices had occurred prior to the cementing job. It really does not matter if it was from the nitrogen migrating after breaking out of the cement or the fact they should never have pumped nitrogen light cement into this well reducing the hydrostatic and allowing an influx from the formation.
It is just the fact that gas “was migrating” behind casing after the seal assembly was set and that is what created the un seen 20 hour bomb.
The true sequence of events that no one could see. What happens now? A lot of things start happening that are impossible for anyone to detect or to see. It is not important how much training you have had, how vigilant you are, how much you like your job or how many children you have.
This includes the driller or anyone else on the rig which have been trained to notice pressure differences, flow differences, gains or losses from the well.
Every monitor on the rig will look normal because it is impossible to monitor the pressure build up behind the casing with the seal assembly in the casing hanger.
The first thing that started happening is the casing you ran in to the well and hung off in the well head on the casing hanger is starting to get lighter and lighter. There is no way to see this. The casing is no longer connected to the rig at all. It has become a permenant part of the well. But it no longer weighs 400,000 or 500,000 lbs.
A compressed gas bubble exerts equal pressure in all directions. UP, DOWN, FRONT, BACK, LEFT, RIGHT AND ANY OTHER DIRECTION YOU CAN IMAGINE. It is like the rays coming from the sun in all directions.
There are two different scenarios I could talk about, but since there was a loss zone in the well and it took 20 hours after cementing for the “well” to kick and the rig explode I am sure the gas was expanding as it was migrating. If it was not; the occurrences probably would have taken place much sooner.
As the gas behind casing was migrating, it was gradually forcing more and more of the 14 PPG mud and cement downward into the loss zone and into the actual oil // gas bearing formation. This is not changing the BHP (bottom hole pressure) of the well because there is a loss zone, but it is drastically changing the weight of the casing. The reason for this is because as more and more mud and cement is replaced with gas behind the casing there is more and more pressure exerted upwards against the bottom of the casing hanger. There are around 205 square inches below the hanger if you base it on a 18.75” X 9.625 casing hanger. But in reality there was another (size step down) in the well casing design because they ran a 7” X 9.625” casing string.
The actual square inch surface area that pressure will react against is 18.75” X 7” = 237 square inches.
By the time the gas had migrated upwards the first 1000 feet or forced away 1000 feet of cement; there was 728 PSI exerted against the bottom of the casing hanger.
If you remember the total weight of the casing was 400,000 to 500,000 pounds. With this 728 PSI now pushing up on the bottom of the 237 square inches of the casing hanger it creates an upward force of 728 X 237= 175,536 pounds. The hanging weight on the hanger now is 500,000 – (subtract) 175,536 = casing weight of 324,464 pounds. The gas migrates another 1000 feet and forces the mud and cement back into the loss zone. The casing weight has lost another 175,536 pounds. Total casing weight is now 148,928 pounds. By the time the gas migrates 1000 feet more there is now a negative casing weight of (-26,608) pounds and instead of the hanger supporting weight; it is now holding pressure and pushing upwards with a force of 26,608 pounds. The actual mud or cement which has been displaced and replaced with gas at this point is about 67 barrels. There had only been 51 barrels of cement pumped during the cement job. The cement would have covered about 2,200 feet behind casing originally or an interval from 18, 336 ft to 16,136 feet.
It must be realized that since the well is now blowing out and the oil and gas is coming from the formation at the bottom of the well there can not be any cement around the casing at the top of the oil and gas bearing formation. Therefore it must have pushed most of the 48 bbls of cement into the formation as described above. There would have been about 3 bbls of cement between the float collar and shoe inside of the casing. There was 51 barrels total cement pumped.
If the gas had migrated 1000 more feet and forced another 1000 ft of mud back into the formation; there would now be about 90 barrels of compressed gas behind casing. The top of this gas bubble would be at a depth of 14,336 feet from the surface and still 9,336 ft below the BOP. The casing weight would now be a negative (-202,144) pounds and this is also the force pushing up on the bottom of the hanger.
Even at this point the hanger could have been blown out of the well head if there was no cement at all around the shoe.
I do not know when they actually displaced the inside of the casing from mud to sea water or how much they displaced, but it would also have an affect; making a greater upward force.
They have now decided to displace the marine riser from 14 PPG mud to 8.6 PPG sea water. This is going to react and increase the lifting forces because the downward forces are being reduced. If they had finished displacing the 14 PPG mud with 8.6 PPG sea water it would have reduced the hydrostatic by an additional 1,404 PSI. This is when the failure occurred and the well kicked and blew out.
The upward force at this point on the casing string and casing hanger was 534,892 pounds above the actual weight of the casing that was ran.
- There was a column of gas in the annulus with a volume of approximately 90 + barrels. It had a bubble pressure equal to BHP (bottom hole pressure) which is 13,000 PSI.
- The top of the bubble was about 14,000 feet ± from surface and only 9,000 feet from the BOP. The well had more or less been displaced to sea water and the hydrostatic at 14,000 feet with sea water would be 6,260 PSI.
- One of two things occurred.
- a) Either the shoe turned loose and the whole casing string blew out and up through the BOP and the blow out occurred behind casing from the annulus only. At this point it only needed to blow out
approximately 200 bbls before gas would be above the BOP stack. That would not take 5 seconds with that type of pressure build up.
- b) The casing actually parted and the hanger and the casing blew up through the BOP and the kick is coming from inside and outside the casing.
- As far as the kick and the burning of the rig it really does not matter at this point which of the two occurred the result is exactly the same and the time for it to occur would have only been milliseconds difference.
- It might make a difference now, concerning the killing of the well. If the casing shoe pulled out of the remaining cement and the casing is intact then the complete casing string blew up out of the hole so the casing hanger must be above the BOP. If this was the case then if the annular was closed it should have at least partially stopped the flow. The casing hanger and seal assembly was 18 ¾” which is the same as the I.D. of the well head and BOP. It would have blown up inside the 21” riser to create enough by-pass for the well to blow out around it between the O.D. of the hanger and the I.D. of the marine riser.
- If the casing parted somewhere below the hanger (which it most likely did) then the hanger itself could actually be in the BOP stack or again it could be above it with casing still inside the BOP.
- Regardless this was failure is equivalent to a 6,740 PSI under-balanced kick with a volume of approximately 100 barrels of compressed gas stored and waiting with a bubble pressure of 6,740 PSI and then an open formation with a BHP of 13,000 PSI following behind. It would have been next to impossible for a driller or anyone else to push the buttons fast enough to close the BOP in time. If the casing and hanger blew into the BOP there would have been nothing in the BOP that could have closed to stop the flow. (I believe this is the case.)
- To my knowledge there is not a condition existing such as this in nature any where on this planet. While drilling formations from one to another; they do not have that rapid of a pressure change, nor do
they have the ability to have that type of stored volume the moment you drill into the formation. This is more like drilling into the side of a compressed oxygen bottle with 6,740 PSI with a electric drill. Normal compressed gasses in bottles of any kind only have 3,000 PSI.
- That Blow out is equal to a 9.25 PPG kick at 14,000 feet under the conditions described above and the gas build up behind casing. I have never heard of a kick greater then 3 PPG as a natural occurrence.
- From what I read there was drill pipe in the hole at the time of the kick and explosion, so if the casing and casing hanger blew up through the BOP there was nothing that could actually close to seal this well. There were no casing rams in the BOP, and even if there had been the driller would not have closed them. If something could close around the casing such as the annular then there would still be flow between the inside of the casing and the drill pipe.
- There was not supposed to be casing in the BOP. Casing had been ran and cemented 20 hours before. The driller would have closed the pipe rams, but they would not close on casing.
- The driller under these conditions probably would have pushed the shears to shear the drill pipe. If he did not, then the automatic system operated when communication was lost to the Pods and the shear rams tried to close automatically; they would not have been able to shear casing with drill-pipe inside. That would be why they did not have enough force to close and secure the well and that is the events that I believe have caused this disaster.
I just do not believe that so many things could have failed at the same time. I believe the BOP worked to the best of its ability, but could not cut because the casing had blown out of the hole. Many drill strings around the world weighing 100s of thousands of pounds have been blown out of the hole. There is no reason that would prevent casing from doing the same thing if gas was trapped behind casing.
If what I have described above is what in fact happened, then they can reinvent the subsea BOPs and install 15 pipe rams and 2 blind shears and they still will not close if this should happen again. They need to make sure they understand the ROOT cause and fix that. Other wise jobs are lost, money is spent and the situation has not changed and the danger is still real.
I am confident they will probably discover that what I have described above happened if they are successful at cutting off the top of the marine riser. But they should consider this as a possibility. Looking at their latest plan it appears they are going to make a first cut on the riser using a large shear. The way I see it they are going to crimp the riser shut when they make this cut. If they close in this well it is going to try to achieve a shut in pressure. That may blow the riser off the top of it and that won’t be good. If they are going to do the first cut with a shear they need to have a good flow path to the recovery vessel and establish flow up to the vessel via choke and kill before they go fooling around with trying to make the first cut. If they were real lucky they might crimp the riser without increasing the flowing pressure inside the BOP and all oil flow would be recovered to the vessel. Just do not try to shut it in at any time after this. If that does not happen then they may have to cut riser with the diamond saw, but if I am correct they will also have to cut through casing and then drill pipe to successfully clear the top of the well bore above the LMRP. If they only get it half done they are going to make the leak worse without having another corrective action. The should also consider the fact as soon as they cut into the riser there is going to be a lot of pressure oil and gas coming out of the cut and it will blind all the cameras on the ROV if it is up close. If that happens they will be trying to work blind at the bottom of the sea.
Also if there are additional strings inside the riser it could break the diamond band blade in the diamond saw. Since they have choke and kill lines hooked up now, why do they not try to flow the oil up to a recovery vessel through the choke and kill lines.
I am guessing at this, but I believe they said once that there was about 1600 PSI flowing pressure and I would have to assume that is above sea water hydrostatic of ±2236 PSI giving an actual well flowing pressure of 3836 PSI.
There are some real intelligent people working the numbers on that end, but it seems to me if they could flow up through the choke and kills to the recovery vessel holding some back pressure at surface to prevent rapid gas bubble expansion the oil and gas column would be much lighter then the hydrostatic of 5000 ft of sea water which is ± 2236 PSI. If they could get enough flow to reduce the pressure inside the BOP so that it was less then 2236 PSI, you would be recovering all the oil and the sea water hydrostatic would prevent oil and gas from coming out of the ruptured riser. I have not tried to run any numbers on this because I do not know exactly what they have hooked up.
[QUOTE=View 2 a ?;37572]looked like eroded dp to me,if the well is making sand, i’d be willing 2 bet on, whatever part of the stack that was holding it lost some of it’s grip. i could only see it in between gushes of oil and could see the disperant rod clearly on the outer edges.[/QUOTE]
We will be seeing some major chages in the view over the next few days. I saw 4 big trucks loaded w/ new riser & some kind of rubber tire like pieces for shock absorbtion/wear deterrent leaving the Smith Services yard this moroning. They are evidently going to have to change out the bottom of the riser. I watched the ROVs inspecting the rise last night & the flow over the bottom 5 or 6 joints was so bad, they couldn’t even get pictures of the flange connections that they were checking further up the hole.
it was pipe, up against the inside of the riser flange, would estimate that it came up til it hit the underside of the hat, and yes i believe there is more than dp being held by the bops, that all the mainstream media ppl report “failed” .
[QUOTE=bnhpr;37550]The rov didn’t have the volume to shift the regulator, had nothing to do with pressure.
That’s why the went down the second time with an accumulator, and it fired.
Everyone here thinks there an expert on BOP’s and who here has ever worked on one? Seen one? Seen a p&id of one? an actual photo of one?
Speak up with real experience. Otherwise stop speculating about a device you know nothing about.
There is no great mystery of failure here. No drama.
The only failure on the DWH, and their management ashore… was people.[/QUOTE]
Well then, let me quote someone who knows:
(Borrowed from http://drillingclub.proboards.com/index.cgi?board=wellcontrol&action=display&thread=4840&page=42 post 1245.)
Makes about as much sense as anything I’ve read.
[B]Re: Cause of Blowout/Fire on Horizon[/B]
« Reply #1245 Yesterday at 3:16pm »You may find this interesting as well
This is only my opinion, I can not prove any
of it, but I think it will come to light.
Everyone is saying they can not figure out what cause the Rig to Explode so quickly, the loss of 11 souls, the failure of the BOP. It is not that hard to figure out. I have been in the drilling business for almost 21 years. I could not get exact information as to casing strengths and all the data that would have been helpful to come up with perfect calculations, but there is only one circumstance and scenario that can cause this to happen in my opinion.
The information has slowly passed across the internet as to all the well data: mud weights, depths etc. I have had to piece and
separate the facts from the fiction to come to my conclusions.
I see where they are holding the Captain responsible for the largest oil
spill in History and saying anyone on that rig could have simply called a time out. I will assure you that that Captain had nothing to do with
this spill, nor could he have prevented it. Nor could have the 11 men
that died or the men that lived through a fiery hell.
In my opinion using my knowledge and experience no one could have stopped what appears to me was the makings of a disaster. They built the 20 hour bomb accidentally and it would have been impossible for anyone to detect what was going on until it exploded.
I believe they made a grave mistake in their design and then continued to make others after it started going wrong.
The secret to this I am sure is when they decided to pump Nitrogen cement into an abnormally pressured deep-water well. They should have never done this is my opinion. The last thing you would ever want; is to end up with gas behind the casing string in a Deep-water well. You do not want gas behind any casing string anywhere.
It is different on a land rig or a surface BOP where you can actually
let the nitrogen surface as it breaks out of the cement. It is not
contained and even if you install the hanger seal you can still monitor
the pressure behind the casing through a well head wing valve. But if
you do this on a Deep-water well as soon as they installed the pack off
in the casing hanger at 5000 ft. it was the same as lighting the 20 hour fuse. The gas continues to migrate and there is no place to monitor it or to bleed it off. The pressure just keeps building.
It is one thing to positively design a well and use all the
data and information from books and manufacturers design criteria
considering known or expected pressures, but wells also need “WHAT IF CALCULATIONS” I call it (negative or what if) Engineering.
Three “WHAT IF” calculations should have been made and
apparently they were not.
-
What if the Nitrogen migrates up the annulus behind the casing after the seal assembly is set?
-
What if the cement job fails altogether and the shoe is not encapsulated and the formation is not isolated either?
-
What if both of these occurred?
I believe these things happened on the HORIZON and that is what has caused this disaster.
Gas has to expand somewhere to relieve the pressure of the bubble as it migrates to surface or to shallower depths.
(MIND YOU THERE SHOULD NEVER BE ANY GAS BEHIND CASING IF ALL IS DONE CORRECTLY).
One barrel of gas from the bottom of this well will increase in size by approx. 884 times when it reaches the surface. This is 884 barrels or 37,142 gallons from the original 1 barrel of gas which entered the well bore at 18,000 feet. Gas expands based on Boyle’s Law.
P1 X V1 = P2 X V2.
I personally believe the nitrogen cement job started the events although it seems other bad practices had occurred prior to the cementing job. It really does not matter if it was from the nitrogen migrating after breaking out of the cement or the fact they should never have pumped nitrogen light cement into this well reducing the
hydrostatic and allowing an influx from the formation.
It is just the fact that gas “was migrating” behind casing after the seal assembly was set and that is what created the un seen 20
hour bomb.
The true sequence of events that no one could see. What happens now? A lot of things start happening that are impossible for anyone to detect or to see. It is not important how much training you have had, how vigilant you are, how much you like your job or how many children you have.
This includes the driller or anyone else on the rig which have been trained to notice pressure differences, flow differences, gains or
losses from the well.
Every monitor on the rig will look normal because it is impossible to monitor the pressure build up behind the casing with the seal assembly in the casing hanger.
The first thing that started happening is the casing you ran in to the well and hung off in the well head on the casing hanger is starting
to get lighter and lighter. There is no way to see this. The casing is
no longer connected to the rig at all. It has become a permenant part of the well. But it no longer weighs 400,000 or 500,000 lbs.
A compressed gas bubble exerts equal pressure in all
directions. UP, DOWN, FRONT, BACK, LEFT, RIGHT AND ANY OTHER DIRECTION YOU CAN IMAGINE. It is like the rays coming from the sun in all directions.
There are two different scenarios I could talk about, but since there was a loss zone in the well and it took 20 hours after cementing for the “well” to kick and the rig explode I am sure the gas was expanding as it was migrating. If it was not; the occurrences probably would have taken place much sooner.
As the gas behind casing was migrating, it was gradually forcing more and more of the 14 PPG mud and cement downward into the loss zone and into the actual oil // gas bearing formation. This is not changing the BHP (bottom hole pressure) of the well because there is a loss zone, but it is drastically changing the weight of the casing. The reason for this is because as more and more mud and cement is replaced with gas behind the casing there is more and more pressure exerted upwards against the bottom of the casing hanger. There
are around 205 square inches below the hanger if you base it on a 18.75” X 9.625 casing hanger. But in reality there was another (size step down)
in the
well casing design because they ran a 7” X 9.625” casing string.
The actual square inch surface area that pressure will react against is 18.75” X 7” = 237 square inches.
By the time the gas had migrated upwards the first 1000 feet or forced away 1000 feet of cement; there was 728 PSI exerted against
the bottom of the casing hanger.
If you remember the total weight of the casing was 400,000 to 500,000 pounds. With this 728 PSI now pushing up on the bottom of the 237 square inches of the casing hanger it creates an upward force of 728 X 237= 175,536 pounds. The hanging weight on the hanger now is 500,000 – (subtract) 175,536 = casing weight of 324,464 pounds. The gas migrates another 1000 feet and forces the mud and cement back into the loss zone. The casing weight has lost another 175,536 pounds. Total casing weight is now 148,928 pounds. By the
time the gas migrates 1000 feet more there is now a negative casing
weight of (-26,608) pounds and instead of the hanger supporting weight; it is now holding pressure and pushing upwards with a force of 26,608 pounds. The actual mud or cement which has been displaced and replaced with gas at this point is about 67 barrels. There had only been 51 barrels of cement pumped during the cement job.
The cement would have covered about 2,200 feet behind casing
originally or an interval from 18, 336 ft to 16,136 feet.
It must be realized that since the well is now blowing out and the oil and gas is coming from the formation at the bottom of the well there can not be any cement around the casing at the top of the oil and gas bearing formation. Therefore it must have pushed most of the 48
bbls of cement into the formation as described above. There would have been about 3 bbls of cement between the float collar and shoe inside of the casing. There was 51 barrels total cement pumped.
If the gas had migrated 1000 more feet and forced another 1000 ft of mud back into the formation; there would now be about 90 barrels of compressed gas behind casing. The top of this gas bubble would be at a depth of 14,336 feet from the surface and still 9,336 ft below the BOP. The casing weight would now be a negative (-202,144) pounds and this is also the force pushing up on the bottom of the hanger.
Even at this point the hanger could have been blown out of the well head if there was no cement at all around the shoe.
I do not know when they actually displaced the inside of the casing from mud to sea water or how much they displaced, but it would also have an affect; making a greater upward force.
They have now decided to displace the marine riser from 14 PPG mud to 8.6 PPG sea water. This is going to react and increase the lifting
forces because the downward forces are being reduced. If they had
finished displacing the 14 PPG mud with 8.6 PPG sea water it would have reduced the hydrostatic by an additional 1,404 PSI. This is when the failure occurred and the well kicked and blew out.
The upward force at this point on the casing string and casing hanger was 534,892 pounds above the actual weight of the casing that was
ran.
-
There was a column of gas in the annulus with a volume of approximately 90 + barrels. It had a bubble pressure equal to BHP (bottom hole pressure) which is 13,000 PSI.
-
The top of the bubble was about 14,000 feet ± from surface and only 9,000 feet from the BOP. The well had more or less been displaced to sea water and the hydrostatic at 14,000 feet with sea water would be 6,260 PSI.
-
One of two things occurred.
-
a) Either the shoe turned loose and the whole casing string blew out and up through the BOP and the blow out occurred behind casing from the annulus only. At this point it only needed to blow out
approximately 200 bbls before gas would be above the BOP stack. That would not take 5 seconds with that type of pressure build up. -
b) The casing actually parted and the hanger and the casing blew up through the BOP and the kick is coming from inside and outside the casing.
-
As far as the kick and the burning of the rig it really does not matter at this point which of the two occurred the result is exactly the same and the time for it to occur would have only been milliseconds difference.
-
It might make a difference now, concerning the killing of the well. If the casing shoe pulled out of the remaining cement and the casing is intact then the complete casing string blew up out of the hole so the casing hanger must be above the BOP. If this was the case then if the annular was closed it should have at least partially stopped the flow. The casing hanger and seal assembly was 18 ¾” which is the same as the I.D. of the well head and BOP. It would have blown up
inside the 21” riser to create enough by-pass for the well to blow out
around it between the O.D. of the hanger and the I.D. of the marine riser. -
If the casing parted somewhere below the hanger (which it most likely did) then the hanger itself could actually be in the BOP stack or again it could be above it with casing still inside the BOP.
-
Regardless this was failure is equivalent to a 6,740 PSI under-balanced kick with a volume of approximately 100 barrels of compressed gas stored and waiting with a bubble pressure of 6,740 PSI and then an open formation with a BHP of 13,000 PSI following behind. It would have been next to impossible for a driller or anyone
else to push the buttons fast enough to close the BOP in time. If the
casing and hanger blew into the BOP there would have been nothing in the BOP that could have closed to stop the flow. (I believe this is the case.) -
To my knowledge there is not a condition existing such as this in nature any where on this planet. While drilling formations from one to another; they do not have that rapid of a pressure change, nor do
they have the ability to have that type of stored volume the moment you drill into the formation. This is more like drilling into the side of a compressed oxygen bottle with 6,740 PSI with a electric drill. Normal compressed gasses in bottles of any kind only have 3,000 PSI. -
That Blow out is equal to a 9.25 PPG kick at 14,000 feet under the conditions described above and the gas build up behind casing. I have never heard of a kick greater then 3 PPG as a natural occurrence.
-
From what I read there was drill pipe in the hole at the time of the kick and explosion, so if the casing and casing hanger blew up through the BOP there was nothing that could actually close to seal this well. There were no casing rams in the BOP, and even if there had been the driller would not have closed them. If something could close around the casing such as the annular then there would still
be flow between the inside of the casing and the drill pipe. -
There was not supposed to be casing in the BOP. Casing had been ran and cemented 20 hours before. The driller would have closed the pipe rams, but they would not close on casing.
-
The driller under these conditions probably would have pushed the shears to shear the drill pipe. If he did not, then the automatic system operated when communication was lost to the Pods and the shear rams tried to close automatically; they would not have been able to shear casing with drill-pipe inside. That would be why they
did not have enough force to close and secure the well and that is the
events that I believe have caused this disaster.
I just do not believe that so many things could have failed at the same time. I believe the BOP worked to the best of its ability, but could not cut because the casing had blown out of the hole. Many drill strings around the world weighing 100s of thousands of pounds have been blown out of the hole. There is no reason that would prevent casing from doing the same thing if gas was trapped behind casing.
If what I have described above is what in fact happened, then they can reinvent the subsea BOPs and install 15 pipe rams and 2 blind shears and they still will not close if this should happen again. They need to make sure they understand the ROOT cause and fix that. Other wise jobs are lost, money is spent and the situation has not changed and the danger is still real.
I am confident they will probably discover that what I have described above happened if they are successful at cutting off the top of the marine riser. But they should consider this as a possibility. Looking at their latest plan it appears they are going to make a first cut on the riser using a large shear. The way I see it they are going to crimp the riser shut when they make this cut. If they close in this well it is going to try to achieve a shut in pressure. That may blow the riser off the top of it and that won’t be good. If they are going to do the first cut with a shear they need to have a good flow path to the recovery vessel and establish flow up to the vessel via choke and kill before they go fooling around with trying to make the first cut. If they were real lucky they might crimp the riser without increasing the flowing pressure inside the BOP and all oil flow would be recovered to the vessel. Just do not try to shut it in at any time after this. If that does not happen then they may have to cut riser with the diamond saw,
but if I am correct they will also have to cut through casing and then drill pipe to successfully clear the top of the well bore above the LMRP. If they only get it half done they are going to make the leak worse without having another corrective action. The should also consider the fact as soon as they cut into the riser there is going to be a lot of pressure oil and gas coming out of the cut and it will blind all the cameras on the ROV if it is up close. If that happens they will be trying to work blind at the bottom of the sea.
Also if there are additional strings inside the riser it could break the diamond band blade in the diamond saw. Since they have choke and kill lines hooked up now, why do they not try to flow the oil up to a recovery vessel through the choke and kill lines.
I am guessing at this, but I believe they said once that there was about 1600 PSI flowing pressure and I would have to assume that is above sea water hydrostatic of ±2236 PSI giving an actual well flowing pressure of 3836 PSI.
There are some real intelligent people working the numbers on that end, but it seems to me if they could flow up through the choke and kills to the recovery vessel holding some back pressure at surface to prevent rapid gas bubble expansion the oil and gas column would be much lighter then the hydrostatic of 5000 ft of sea water which is ± 2236 PSI. If they could get enough flow to reduce the pressure inside the BOP so that it was less then 2236 PSI, you would be recovering all the oil and the sea water hydrostatic would prevent oil and gas from coming out of the ruptured riser. I have not tried to run any numbers on this because I do not know exactly what they have hooked up.
OOPS, didn’t see that BigMoose had already posted this.
Really? This is really what happened, Admiral?
“BP’s containment cap over a ruptured Gulf of Mexico well was removed Wednesday [B]after a robotic vehicle apparently bumped into a cap vent and closed it,[/B] raising the possibility of hydrates forming, said Coast Guard Adm. Thad Allen, the government’s response manager.”
http://www.cnn.com/2010/US/06/23/gulf.oil.disaster/index.html?hpt=T2
I feel ill.
“They built the 20 hour bomb accidentally”… super discovery, knowing bhp, thief zones, just to name a few, Do it right and be finished with it, move on to the next step, they would have easily made their money back.
[QUOTE=company man 1;37519][QUOTE=GunsnHoses;37458]I know this thread has jumped the shark, but pull-ease, CM, lets try and keep the tinfoil hat stuff down, OK?
Enterprise ROV 2 [I]clearly[/I] shows the cap in place at 9:45 EDT 2010-06-22.
Well it wasn’t firmly in place between 2:00 & 4:00 this morning. In fact it blew off the top of the stack. Make a tin foil reference when you go back & review tape between those times.[/QUOTE]
Is it possible that BP is sending us loop video sometimes instead of live feed? I reported @ 2:00 AM monday morning about the top hat blowing off the stack & what was going on live between 2:00 & 4:00 AM. I was then accused of sensationalism & being a member of the tin foil brigade. When they put the cover over the well Monday morning it fit over the whole flange of the BOP all the way down to the annular. Then last night I saw what appeared to be the top hat in the same exact placement as it had been. I know there is monkey business going on at least with their reporting the numbers. Sunday for intance they reported having one of the highest recovery days so far & the Riser wasn’t even hooked up half the day & the Q4000 was also disconnected from the hose for at least 4 hours in the afternoon. All this cloke & dagger we’re smarter than you shit must stop. If the COast Guard command won’t stop it then he has to be replaced by someone who will.
[QUOTE=View 2 a ?;37584]“They built the 20 hour bomb accidentally”… super discovery, knowing bhp, thief zones, just to name a few, Do it right and be finished with it, move on to the next step, they would have easily made their money back.[/QUOTE]
Made their money back? With about 500% interest so far, not counting the billions of cubic feet of gas they would have made. That in itself should be an inducement for operators to perform the proper stpes in well control. If Corporate BP doesn’t have a safety reason to fire & take cover off of guilty parties for killing so many & destroying so much then how about the money they cost the shareholders? Wouldn’t that make someone just a little hot? Whoever all the guilty are, they cost their own company billions & billions at the very least.
[QUOTE=dell;37553]The culture of snobbery, if not of safety, seems to run very deep. And he’s not Amoco: http://www.nytimes.com/2010/06/23/business/23dudley.html?scp=1&sq=dudley&st=cse[/QUOTE]
This is quite upsetting. He has had 64 days & still hasn’t studied the root cause of the disaster? Maybe it would do him some good to read this thread.
[QUOTE=OldHondoHand;37580]OOPS, didn’t see that BigMoose had already posted this.[/QUOTE]
It’s funny how other unwashed unlearned minds both inside & outside of the industry are coming to very parralel, very close conclusions. I wish BP wasn’t so much smarter than the rest of us. Then they might be able to humble themselves & admit to their wrongdoing. There is one particular point this gentleman points out that got passed me. He rightly points out that due to the casing string being tapered that the hydraulic area of force was actually much greater than what I had posted, because you are talikng about a total upward force of 7" X 18 3/4". This makes the cross sectional area even greater & more sensitive to annular pressure effects.
I cannot believe how much dispersant they are using right now. It’s clouded the entire area around the BOP…can’t even see a bit of it. Enterprise 1 was showing the entire BOP when a cloud of dispersant consumed the whole thing. Now they’ve come up a bit closer. I think they’re spraying more dispersant than there is oil coming out of the riser.
[QUOTE=company man 1;37587]Made their money back? With about 500% interest so far, not counting the billions of cubic feet of gas they would have made. That in itself should be an inducement for operators to perform the proper steps in well control. … Whoever all the guilty are, they cost their own company billions & billions at the very least.[/QUOTE]
One would think that this: http://finance.yahoo.com/echarts?s=BP+Interactive#chart1:symbol=bp;range=5y;indicator=volume;charttype=line;crosshair=on;ohlcvalues=0;logscale=on;source=undefined would make a whole lot of people in a whole lot of places sit up, take notice, and, if need be, clean up their act.
Since 4/20/10, BP has lost just about half of its market capitalization (share price x shares outstanding), something like $90b. Options, stock grants, company stock investments in retirement accounts, all of that, washed away.
And all to attain a savings of, what, $22m?
They are about to put the tophat back on if anyone is interested.
[QUOTE=Walton;37597]They are about to put the tophat back on if anyone is interested.[/QUOTE]
And the carrousel of stupidity goes on & on. Just got word from a good friend that is on a platform drilling rig in less than 200’ of water. It seems they have been waiting on a drilling permit for a week now to continue their program. I was not told specifically whether it was a new drill or permit to modify, but it shows the way things are going to go now in the GOM as a reaction to this disaster. It looks as if the only ones left to drill will be BP.
BTW, has anyone heard of a back up plan for containment since they can’t keep the cap on for more than a day or two at at ime anymore?
The “cloudy” stuff is really green dye in the methanol ect coming out of the bottom of cap. They need the dye to see what is happening down there.
[QUOTE=Walton;37592]I cannot believe how much dispersant they are using right now. It’s clouded the entire area around the BOP…can’t even see a bit of it. Enterprise 1 was showing the entire BOP when a cloud of dispersant consumed the whole thing. Now they’ve come up a bit closer. I think they’re spraying more dispersant than there is oil coming out of the riser.[/QUOTE]