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Message
re: Is the Integrity of the Well Failing?
Posted on 6/16/10 at 11:23 pm to supatigah
Posted on 6/16/10 at 11:23 pm to supatigah
quote:
if the relief well will work because the bop and the first two sets of casing (36 and 22 inch) may have already collapsed
i find it extremely unlikely the 36" and 22" would have collapsed if for no other reason than the 22" x 36" annulus is completely filled w/ cement. also, i cannot really imagine how a collapse load could have been applied to those strings. the pressure inside of the 22" is much higher than when it was run -- making a burst load possible -- but a collapse load pretty much impossible as the external pressure has not changed throughout this (the overburden of the gulf of mexico + sediments).
in any event, this well is flowing uncontrolled at the seafloor, obviously necessitating the relief well. let's say the wellhead failed the BOP's fell over. it doesn't dramatically change the pressures at play.
2
Posted on 6/16/10 at 11:24 pm to oilfieldtiger
quote:
in any event, this well is flowing uncontrolled at the seafloor, obviously necessitating the relief well. let's say the wellhead failed the BOP's fell over. it doesn't dramatically change the pressures at play.
Precisely. Nor does it change the fact that the relief well will kill the well.
Posted on 6/16/10 at 11:27 pm to MoreOrLes
to put it bluntly, I have completely lost faith in bp and the Feds and what they are reporting to us. I think they are holding out hope that the relief wells can stop the flow and that is the end all and the be all. If the relief wells dont work or they arent completed in time then bp and the Feds will shrug and say they did all they could.
the fact that this has become a politically charged issue when it is clearly an environmental issue first and foremost pisses me off to no end. IDGAF about Obama's energy policy right now, I care about a well flowing uncontrolled under the sea with Hurricane season upon us and no end in sight
what happens to the already weakened well/bop if a hurricane passes over it?
the fact that this has become a politically charged issue when it is clearly an environmental issue first and foremost pisses me off to no end. IDGAF about Obama's energy policy right now, I care about a well flowing uncontrolled under the sea with Hurricane season upon us and no end in sight
what happens to the already weakened well/bop if a hurricane passes over it?
Posted on 6/16/10 at 11:27 pm to supatigah
quote:
you think so doctor?
look, i'm trying to answer you honestly.
the point is that w/ the rig adrift, but in calm seas, the load imparted to the wellhead was likely far less severe than actual design constraints. we'll never know for sure, but based on the fact that the wellhead inclination doesn't appear to be very far from vertical, it would appear the wellhead system was not yielded during the drift/sinking.
when you're spudding in subsea wells, there are very tight vertical constraints placed on wellhead systems -- w/ something like 1-1.5 degrees away from vertical being the limit of what people will accept. if the wellhead was leaning at something like 4 or 5 degrees, it would be obvious w/ the naked eye.
This post was edited on 6/16/10 at 11:31 pm
Posted on 6/16/10 at 11:37 pm to supatigah
quote:
what happens to the already weakened well/bop if a hurricane passes over it?
well, subsea BOP systems use a combination of flex joints on top of the BOP and immediately below the rig floor to allow for vessel motion at surface and to keep stop the riser from being one huge, rigid, lever that can exert torque on the wellhead. w/ a conventional rig up, you're only real option during a hurricane is to suspend operations and leave.
it was my understanding that they were building this kind of flexibility into their containment system by using hoses on bottom, which would allow a vessel to remain on location during a storm but i do not know for certain.
Posted on 6/16/10 at 11:40 pm to oilfieldtiger
moving past the rig collapse event to the events of now
you do understand that what he is saying is that the "leaning" weight of the top of the well (the bop/the casing/the cement) working against the unstable sea floor coupled with the damaged nature of the bottom of the well coupled with the intense amount of internal erosion the well bore material is seeing from uncontrolled flow is what could potentially lead to his wellbore "collapse" theory.
right?
he is supposing that the sheer weight of all of the bop equipment and casing and cement at the top of the well is working against its stability at the middle and the bottom of the well.
you do understand that what he is saying is that the "leaning" weight of the top of the well (the bop/the casing/the cement) working against the unstable sea floor coupled with the damaged nature of the bottom of the well coupled with the intense amount of internal erosion the well bore material is seeing from uncontrolled flow is what could potentially lead to his wellbore "collapse" theory.
right?
he is supposing that the sheer weight of all of the bop equipment and casing and cement at the top of the well is working against its stability at the middle and the bottom of the well.
Posted on 6/17/10 at 12:00 am to supatigah
quote:
you do understand that what he is saying is that the "leaning" weight of the top of the well
yes, this is why there are such tight verticality guidelines associated w/ the tophole sections of the well.
i understand what he's saying, but he's making some logical leaps. they did install burst discs in their 16" casing string, likely to assist in producing the well if they had an exploratory success. if the burst discs did rupture, it would likely involve pumping more mud at higher rate, but does not condemn the entire relief well process. to take that piece of information and then say that the well up to that point is compromised is just not true. this also was not the reason the top kill was unsuccessful.
the rupture discs fail and vent pressure to the trapped annulus behind the 16" casing, which is set 6500' below the mudline and laps 18" casing that was set 4000' below the mudline. if the well is flowing behind the 7" x 9 7/8" string, there may have been sufficient pressure on those discs to fail them; however, the path of least resistance for the oil at the moment is still all the way up to the seafloor. if this were not the case, then you would end up w/ a phenomenon known as an underground blowout, where there is controlled flow from one formation to another -- everything happening downhole.
i agree that the components are likely experiencing some erosional deformation given the flowrates involved, but i don't believe that the well will crater in on itself. and even if it did, the relief well would still kill it.
Posted on 6/17/10 at 12:03 am to oilfieldtiger
quote:
i agree that the components are likely experiencing some erosional deformation given the flowrates involved, but i don't believe that the well will crater in on itself. and even if it did, the relief well would still kill it.
from your lips to God's ears
Posted on 6/17/10 at 12:08 am to supatigah
quote:
from your lips to God's ears
the key is being able to circulate from the bottom. all you're trying to do is fill it w/ enough kill weight mud that it will stop flowing and allow cement to set up. granted i have no inside info, so i'm just talking about what has been made publicly available.
there are some that have said all along that removing the BOP's would be the riskiest, but potentially fasted solution, as the flowrate would go so high so fast that the formation would sand itself up and cease to flow.
This post was edited on 6/17/10 at 12:09 am
Posted on 6/17/10 at 12:37 am to oilfieldtiger
quote:Or on the periodic ROV mission they secretively label "Inclinometer Montioring" where they put a bulls eye on the well head...
if the wellhead was leaning at something like 4 or 5 degrees, it would be obvious w/ the naked eye.
Posted on 6/17/10 at 2:27 am to Taxing Authority
quote:
Well first off his theory on why Top Kill failed is completely wrong. Top Kill didn't work because they were basically trying to bullhead a well without a closed BOP. It never had much of a chance at working because the mud simply took the path of least resistance, out the top of the well. His reasoning on why it didn't work is 100% incorrect. Also, Barite is not a white powder, it's brown.
No it is not. You say the top kill didn't work because it was going out the top and that prevented it from building pressure. This is not correct.
The top kill started and the oil stopped coming out as mud went down the well. At this point in the operation mud was pushing the oil back down or at least replacing it in the well.
The problem came when the mud reached the rupture/break/opening. At that point the mud basically just stopped going further down the well and started going sideways into the surrounding seafloor.
For argument sake lets say the leak is at 1000 feet. The mud made it down to 1000 feet and then went into the seafloor at that point. Capacity for the mud to go out the side was basically unlimited.
Junk shots were then put in play. Hoping that as the junk went into the surrounding ground at the point of the leak that it would plug up the channels in the earth that the oil had dug. It didn't.
So the mud made it to 1000 feet (if that is where the leak is) and wouldn't go any further.
Obviously the needed something more like maybe 1600 feet of mud to plug the well. I use these numbers just as examples they are surely wrong but the concept is correct.
Now all you have to do to plug this well is to replace the oil going up with mud or cement. To do this at the bottom will be much easier because as the mud is injected into the flow of oil the mud flow rate doesn't have to be so great that it goes down like was the case with the top kill.
If the flow is 50K barrels a day and the pump mud at 25K barrels a day rate (much lower than they really will) then after a short time half of the material in the pipe will be mud and half will be oil.
The oil weighs less and actually more of it will be ejected out the top than the mud. Now if you pump mud faster you displace more of the oil with mud. At some rate the mud will actually have sufficient weight to plug the well. At that point cement is pumped in and after it hardens (much quicker than normal concrete) the well is dead.
Posted on 6/17/10 at 2:30 am to omegaman66
Actually the mud needed to reach around 13,000 feet based on the pressures I was quoted. They never came anywhere close to getting mud that far down and wouldn't have whether the casing is ruptured or not. We know what mud weight it took to hold back the gas therefore you know what pressures the formations are under. Since there is no mud left in the well, it's pretty simple to figure out what pressure you need to create with your kill mud to stop the well from flowing. You also know the maximum density kill mud that can be pumped. The rest is pretty simple.
But thank you for your informative lecture.
But thank you for your informative lecture.
This post was edited on 6/17/10 at 2:42 am
Posted on 6/17/10 at 2:41 am to redstick13
They were measuring how much they pumped. They suspected a problem with a leak in the well. The pumped enough mud to push it down. As they pump they can't tell where the mud is going. They stop pumping and all the mud gets blown out in X amount of time. The pump more mud and should have it deeper in the well. The stop and it takes the same amount of time to eject the mud. Meaning they had reached the point of the leak and all the mud was escaping. At that point it is obvious they need to plug the well rupture... therefore the top kill. Top kill wouldn't stop the lateral flow. Top kill aborted.
Posted on 6/17/10 at 2:47 am to omegaman66
Were they measuring how much was pouring out the riser while they were pumping? They can't accurately measure how much oil is coming out so I doubt they could accurately measure how much mud was pouring out while they were attempting the top kill. If they can't, then how do they know where the mud was going? It doesn't matter if they measure how much they were pumping if they don't actually know how much was going into the well.
This post was edited on 6/17/10 at 2:51 am
Posted on 6/17/10 at 2:49 am to redstick13
Believe it or not I understand lost circulation zones (the same as your'e proposing with the ruptured casing) because I deal with them almost weekly. I actually just got done healing one up less than 2 hours ago. I also understand well control as I've been to well control school and filled in a few kill sheets.
This post was edited on 6/17/10 at 2:55 am
Posted on 6/17/10 at 2:55 am to redstick13
Not measuring the flow. Measuring the time it took to eject the mud. ex. Pump 5 hours and when you stop it takes say... 5 minutes to eject all the mud. Then you pump again for 5 hours at a higher flow rate. This means you pumped more mud. Yet it took the same amount of time to eject the mud. This means the mud is reaching a point insufficient to kill the well before it all starts moving laterally into the surrounding sea bed because you didn't get it any deeper down the well.
This post was edited on 6/17/10 at 3:11 am
Posted on 6/17/10 at 8:52 am to Taxing Authority
quote:
Or on the periodic ROV mission they secretively label "Inclinometer Montioring" where they put a bulls eye on the well head...
wellhead systems already feature 1 or 2 bullseyes that are bolted onto the very top section of the 36" casing when it is jetted in. The BOP system typically features a bullseye on the lower section of the stack and another on the LMRP.
all of these bullseyes are visible / accessible by ROV's during normal operations.
Posted on 6/17/10 at 10:36 am to oilfieldtiger
So it seems this is a race against time. The longer the relief wells take the greater the risk of his theory coming true.
I do not think he was saying this is what is going to happen but more of his concern of what could happen. Which I think should get attention.
What happens if the relief wells do not work?
I do not think he was saying this is what is going to happen but more of his concern of what could happen. Which I think should get attention.
What happens if the relief wells do not work?
Posted on 6/17/10 at 11:55 am to Impotent Waffle
I don't know. They could just start pumping oil and that would help a lot I would think. The reservoir is not a lake of oil but more like a sponge of oil. The oil can only move through it so fast. Get to rigs producing oil where they think it would do the most good and I would imagine the oil flow would drop of dramatically.
But I think they would on a subsequent attempt to there planned kill method drill slightly deeper... penetrate the reservoir and try to inject into the reservoir or something to plug it up there.
This of course is just me making crap up.
But I think they would on a subsequent attempt to there planned kill method drill slightly deeper... penetrate the reservoir and try to inject into the reservoir or something to plug it up there.
This of course is just me making crap up.
Posted on 6/17/10 at 3:18 pm to omegaman66
quote:
When a well is completed the casing is perforated at the production zone and then the formations are intentionally hydraulically fractured.
doubt they frac'd in this case.
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