I was reading up about the cause of the Deep water Horizon disaster and was trying to understand what options you have if the only way you can stop the kick in a well is to activate the blind sheer ram and cut the drill string?
I understand that the reason the deep water horizon could not be contained was because the blind sheer ram failed to fully cut the drill string and isolate the well?
Do oil companies just abandon the well or would they drill a relief well and somehow remove the drill string and continue to use the existing well?
glad this was a DWH question and not someone on the job looking for help with this!
Me too!
In answer to your question. Maybe, it would all boil down to the economics. Also bear in mind that there are often multiple wells per field.
don't think you'd be that bothered about getting the drill string back but you'd probably want to drill a relief well and fill that MF full of cement*
* proper oilfield parlance...
i read the title to this and thought bloody hell someone from stw is in trouble....
cost, its all about cost
It would also depend on what your local regulator allowed you to leave behind, although in a Deepwater Type scenario, not recovering plant you were supposed to after a disaster of that scale would be the very last of your regulatory worries.
i read the title to this and thought bloody hell someone from stw is in trouble….
me too!
When work experience goes wrong....
Still could be worse, could be asking
"how do you shutdown the reactor core when all safety systems have failed due to a planned power failure test scenario...."
Or "How long until meltdown after the earthquake tidal wave overtops your sea defences and floods the diesel CW pumps?"
When all else fails try asking on STW, someone is bound to know the answer and save a catastrophe
Asking for a friend 😂
Blind sheared rams? No problem.
I'd like to think I could cobble together a reply for most posts on here but this one, jeez, proper niche! 🤣
No. I know there are a few on here who work in the O&G industry so thought I'd ask away.
You should all feel honoured that I have such confidence in you all!
Nuke it from orbit. It’s the only way to be sure.
oh no we dont
(well i dont, valves)
I think this is a "it depends" answer but you probably wouldn't plan on using the existing well for anything and recovering the drill string would be the least of your worries. It'd be all about making sure the well was properly killed so not relying on the shear rams lasting for ever.
I was expecting the solution to include lots of concrete.
Should then last long enough for it to become someone elses problem when the concrete breaks up a few decades down the line.
heavily circumstantial
But in my case i point at the bolt cutters and well control cross over then GTF off the floor long before it gets to this situation.
i read the title to this and thought bloody hell someone from stw is in trouble….
me too!
and me... It must be one heck of an Omnishamble shaped Cockwombled Clusterf*ck if it's so bad on an actual oilrig with an actual issue now, the answer must lie on a cycling chat forum....
But I guess worse has been sorted on here.....
Next question..
"Any explosives experts in the house? Need help choosing the red or blue wire"
Been working in drilling for 13 years and I have never been involved in a job where the blind shear rams were used in anger.
Actually, I tell a lie. I was on a job where the shaft of the drawworks cracked while drilling the reservoir section. I think they had to shear the pipe while they repaired/changed out the drawworks but I have no idea what happened because I was kicked off the rig as soon as it became apparent there wasn't going to be anymore hole dug anytime soon.
From my days if theory and no practice.
1. Controls the whell.depending on the bop assembly
2. Monitor
3. If the drill string is to be removed a wireline operation or fishing operation.
All theory here. And never goes to theory
When I saw there'd been 23 replies to this thread I thought, 'eh, 23 drilling engineers on here' but no, as usual there's only 1.5.
Bruce Wee being 1 & The Brick being the .5 😉
<Nuke it from orbit. It’s the only way to be sure.>
Go big or go home:
<ahref="https://www.bibliotecapleyades.net/ciencia/ciencia_uranium27.htm">
Well this morning I had someone bring a knackered laptop to me to fix and I was thankful that I didn't have to activate the blind sheer ram and cut the drill string.
Sorry, that link was crap... But I seem to be having problems posting links and videos.
Anyway, it is just a regular video of a nuclear bomb being used to seal a gas blow-out.
When I saw there’d been 23 replies to this thread I thought, ‘eh, 23 drilling engineers on here’ but no, as usual there’s only 1.5.
I've seen There Will be Blood. That's got to count for something, surely.
What I've seen in a similar circumstance (mega simplified).
Original rig sits on the well with the rams shut. Rig two comes along and drills a relief well. Rig two then uses directional to intersect the original sheared drill string and pump two mahoosive cement barriers down the original. Rig one pulls the top section of the sheared string to surface and plugs the top hole. Both rigs move on to the next job.
Original rig sits on the well with the rams shut. Rig two comes along and drills a relief well. Rig two then uses directional to intersect the original sheared drill string and pump two mahoosive cement barriers down the original. Rig one pulls the top section of the sheared string to surface and plugs the top hole. Both rigs move on to the next job.
At last, we have a serious answer! Thanks
MR HDBanana - BEST ANSWER ! thanks for that - could have saved BP a bob or two if they'd sneaked that in to the GOM and would have made the film a bit more interesting.....
Sorry, that link was crap… But I seem to be having problems posting links and videos.
Anyway, it is just a regular video of a nuclear bomb being used to seal a gas blow-out.
Impressive achievement for the team that did it but depressing to see the quantities of gas involved and the measures that needed to be taken. I wonder how many days the well burnt for.
@flanagaj as I said, hugely over simplified but you get the jist. I've been in mobile drilling for close to 20 years and every day is still a school day! Functioning the BSR's is really a beyond the point of no return moment but (I have seen it done though) all Drillers are empowered to do it. Usually the annular, choke/kill and diverter are the first points of call.
Macondo was a unique set of circumstance that all aligned, I was in a position where I was hearing quite directly about all the circumstances.
That said, we also had Piper. I worked on Piper B for a bit and nothing is as humbling as looking at the flashing bouy where Piper A stood, especially on the anniversary. I do believe that our regulatory regime will prevent a repeat though. Nowt to do with well control but still.
I think if you log in to the IWCF website you can do Well Control Level 1 as a freebie if you want some oversight.
Off to work in the morning. I'll ask.
Answer may/may not be correct.
https://goo.gl/images/6ZcZx2
Impressive achievement for the team that did it but depressing to see the quantities of gas involved and the measures that needed to be taken. I wonder how many days the well burnt for.
Google darbvaza hole / gates of hells in Turkmenistan
A Soviet gas well blow out they tried to "burn out" it's been burning since 1971.
@flanagaj as I said, hugely over simplified but you get the jist. I’ve been in mobile drilling for close to 20 years and every day is still a school day! Functioning the BSR’s is really a beyond the point of no return moment but (I have seen it done though) all Drillers are empowered to do it. Usually the annular, choke/kill and diverter are the first points of call.
Macondo was a unique set of circumstance that all aligned, I was in a position where I was hearing quite directly about all the circumstances.
That said, we also had Piper. I worked on Piper B for a bit and nothing is as humbling as looking at the flashing bouy where Piper A stood, especially on the anniversary. I do believe that our regulatory regime will prevent a repeat though. Nowt to do with well control but still.
I think if you log in to the IWCF website you can do Well Control Level 1 as a freebie if you want some oversight.
Very interesting to hear from someone with first hand experience. I have been reading a bit more and like you say. Operating the BSR is the big red button with a no a return. I would not want the responsibility for pushing that button in case you got it wrong 8-|
One of the drillers I used to work with told me a story of using the shear rams. When you lose part of the drilling assembly down the hole you have to go through a procedure calling fishing, basically using specialist tools on the end of the drillstring to grab the 'fish' and bring the assembly back to surface. They had been fishing for several days and had managed to grab the fish but it had fallen of again a number of times. Finally they got the fish to surface and the driller said close the shear rams so that if the fish dropped again it would only fall onto the rams and could easily be recovered. ...... Unfortunately, the fish was 90ft long and the shear rams were only 30ft below the drill floor - you can see why the driller was not the most popular person on the rig after that.
Stupid question, is recovering the drill string that important? to my laymans eyes it's just a load of metal pipes yeah??
Second stupid question: the pressure in the well is presumably driven by the pressure of the rock dome above the oil pushing down on that dome, so deeper = more pressure. What happens when the oil is removed? Subsidence, or is something pumped back down to take it's place?
/everydaysaskoolday
The main reasons why you would want to recover the drill string are:
- You want to keep on drilling, and you cannot do that with a “fish” in the way.
- The stuff you have on the end of the drillstring (Logging While Drilling tools, directional drilling kit, the bit etc) is expensive... if you leave it down there then there is a considerable charge payable.
- Some LWD tools contain radioactive sources, and you have to do pretty much all you can to recover them.
Ultimately, if you cannot recover the fish then you have to call it a day and TD the well, or drill around the fish (called a sidetrack). Apart from the case with nuclear tools, the decision to “go fishing” or “sidetrack” is mostly down to economics... how long it will take you to fish + the chance of being successful against the cost of drilling the sidetrack.
@ maxtorque. Oil reservoirs aren't "reservoirs" in the way you might be thinking (a big pool of oil). I'm sorry if this isn't your base assumption but I have encountered it before.
The oil is within the porespaces of the rock (Porosity) - Think stacked tennis balls and oil is in the voids. As oil is drawn out water (in general) fills the pore space. This water can either come from adjacent areas and / or be injected to improve recovery.
Having said that when you draw enough oil at the rock can subside - check out Ekofisk subsidence.
Whats a fish ?
Not the obvious answer, obviously
Anything in the hole you want to get out that isn't attached to the top drive (the drill if you will)
Be it a broken drill string or part of a completion that's been cut prior to recovery during well abandonment or slot recovery -or as in the last fishing job I was near ..... 8000ft of birdsnested wireline cable that went south during a drum change over a live well.....
@maxtorque: to give a slightly more pedantic answer look at the Material balance equation
Essentially there’s lots of potential components to your reservoir drive mechanism (what drives the oil/gas to surface). Primary drive is where you rely on expansion of the oil/gas/water and compaction of the rock formation. Compaction is generally pretty small relative to the energy from the reservoir fluids. Ekofisk is a whopping thick layer of chalk (hundreds of meters thick - related to the white cliffs of Dover) so the compaction adds up to noticeable subsidence at surface. If primary drive doesn’t give good enough recovery then try injecting fluids from surface, either water or gas for secondary drive.
I use Ekofisk subsidence as a good example of something that is supposed to be impossible actually happening.
It's why I'm very much against fracking. Sure, it'll probably be fine but is it really worth taking the risk of massive environmental damage for resources that may or not be there?
If you're a Tory, the answer is clearly yes.
I have nothing to do with oil & gas but am now doing that level 1 well control course on the Iwcf website. Very interesting actually and another thing for me to pontificate knowledgeably about to my kids 😂
I find the whole industry fascinating and wish I had done that MSc in Drilling Engineering 24 years ago when I graduated with my Chemistry degree! The thing I find interesting is having to get the hydrostatic pressure of the drilling mud correct so that overcome formation pressure but without fracturing the formation because the hydrostatic pressure is too high.
To think that formation pressure is in 1000s of psi you can see why well control is important. This video below whilst poor quality is quite mind blowing to watch the drill string being blown out the well like a piece of cotton.
As an idea of the pressures and temperatures that can be involved. I worked on the design of a gas riser ( the pipe from the seabed to the surface) for 780bar (eleven thousand psi) pressure and 200 centigrade flowing temperature. if I recall there were some bits of pipe with a 76mm wall thickness of custom steel (X70+)
One of those jobs where you have to think how you are going to buy the steel and get something made for a product where you might normally just select it from a catalogue.
Seeing as there a bit of interest in this, here's a bit of education:
As a rule of thumb, the pressure you see as you drill down into the earth is governed by the density of salty water, that is around 0.45 psi/ft. So at 10,000 ft the pressure is 4500 psi or 300 atmospheres. This is called normally pressured. Rock strength is typically around 0.7 psi/ft, so to frac rock at 10,000 ft you need to apply a pressure of 7000 psi.
In some parts of the world you get what is called overpressure, this can be due to a number of reasons one of which is rock compaction. As layers of rock build up due to accumulation of sediments, the rocks below compact. This would normally expel water, but if the water is trapped it can lead to pressures in excess of normal. The Macondo well was drilled to over 18,000 ft, if normally pressured that would be 8000 psi, in fact reservoir pressure was over 12,000 psi. This was known about and was not the cause of the disaster, that was more due to a failure to properly cement the casing (pipe lining) in the well.
Macondo well was drilled to over 18,000 ft, if normally pressured that would be 8000 psi, in fact reservoir pressure was over 12,000 psi
So is that what caused the kick?
If everything had gone to plan would that have been a routine event to deal with. Eg, shut the pumps, close the annular preventer and then circle the formation fluids out before pumping denser mud down the string?
Sorry if that's a simplistic explanation.