ROV attempting to activate Deepwater Horizon Blowout Preventer
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May 17, 2010 by
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Hammer,
Not to keep shooting your ideas down, but whatever could be injected to stop the flow, has to be able to withstand the differential pressure of what is in the wellhead to the seawater, I estimate that to be around 800psi, foam wouldn’t do it, because I have never heard of one that would expand under 3,000psi pressure, or has the compressive strength to withstand 800psi differential. So whatever is injected has to have at least that value for its compressive strength, and be capable of achieving that strength within a few seconds.
Isn’t there a chemical epoxy that will flash set?
To pump in? Anyone?
Horizon37: if your estimate is correct, and I don’t disagree with you, then it is higly possible that the riser would withstand the internal pressure if the kink was plugged off. You agree? Isn’t that riser good for 1400 psi burst originally? You think differential between seawater is 800 psi?
Have you ever tried to keep a hydraulic system from plugging an orifice? I have worked on multimillion dollar robots stopped dead by a tiny piece of Teflon tape. with a much higher pressure differential than that. It is amazing how much stronger materials are when pressure is compacting it against an orifice.
if you start throwing solids into virtually any restricted hydraulic system and it will plug.
"if you start throwing solids into virtually any restricted hydraulic system and it will plug. "
That is one idea I think should be included in future BOPs.
We’re pretty sure, I think, that the cutoff/sealing systems tried to deploy. It seems likely that flow is somewhat restricted in the BOP due to partial deployment (otherwise, we should be looking at between 30-50K barrels spilled per day).
So it’s too bad we don’t have the ability to inject some packing materials below the cutoff shears (I’m not saying we have the ability to do that–just wishing we did).
There is a good chance we could pretty much stop up the blowout, inside the BOP, which is built to handle the well pressure. There could also be a system, just ahead of the cutters, to put in a metal grid to give the packing stuff more to hang on to. If the pipe was blocked by the drill stack, or something else, and the grid couldn’t deploy, the obstruction would provide the necessary crap for the packing material to hang up on to clog the opening.
I’m envisioning some sort of high-tensile-strength cable, with perhaps a followup aggregate mix.
Add a high-pressure port just downstream of this where cement could be injected, and this well could have been shut down.
Cut and seal if possible. If the cutters are obstructed, barf in a load of packing and cement the well.
Just tossing a couple of pennies at a time into the discussion.
If there is an accessible collar/port below the BOP (there seems to be some debate on this) and if there is a choke condition within the BOP or first riser section (i.e., the higher PSI rated portion of the system), could frac balls be pumped in to further reduce the flow rate? At the worst, it seems they could help gauge the size of the restriction by monitoring what size passes through the riser.
Petroleum Engineer1
The odds of having a tool joint or heavy metal at the shears is way higher than that, there is one there on every BOP test because the test plug is right below the shear rams, and the BOPs are tested weekly, or after every casing run. There is heavy iron there on every casing run for the casing running tool and and subsea cement plug launcher. But taking a kick during any of these operations so extremely rare it’s bordering on never. And if any of these tools were to be accidentally sheared off it could leave the well in an unrepairable situation, with un-retrievable junk in the wellhead.
If you want to compare parachutes to dollars, say it cost a trillion bucks to install the chutes, some duffus tries one out net loss 1 trillion, if no duffus uses one? net loss 1 trillion, no chutes are installed and no duffus tries it because he has no chute net loss 0.
In regard to the containment dome, is anyone certain where it will be placed? I read in one post that the riser and drill stem may be cut above the LMRP to provide a single discharge outlet. If that strategy is pursued and the containment dome placed immediately over the subsea stack, aren’t they pretty much sacrificing any chance of controlling the leak with existing equipment? I don’t see how an ROV can perform any operations on the current equipment if its covered with an oil-filled containment dome.
drill the pipe and insert in it an
Shape memory alloy
see en.wikipedia.org/wiki/Shape_memory_alloy#One-way_memory_e…
‘I read in one post that the riser and drill stem may be cut above the LMRP to provide a single discharge outlet."
I said that. I’m just guessing.
Seems like the news today that BP has sealed one leak indicates they’re going to reduce the points at which the Riser is leaking and control that.
I keep seeing a couple of what look like caissons in the construction pictures, so maybe they’ll use more than one and just put them over a couple of points?
Like I said, I’m no authority.
However, I also understand there is considerable riser left in a vertical condition over the BOP. So they could, in my theoretical universe, cut off the main part of the Riser, cap it with a caisson, and still have access to the BOP.
Third and last point is that the relief well they’re drilling is going right though the same production area as the original blown out well (using slant drilling).
So, (again, speaking as a layman) I see no reason why, after sealing the blowout, BP won’t just back off a little way from their cement plug and establish a productive well from the relief well. Then they’ll salvage the BOP and whatever else they can from the original well off the ocean floor.
"I read in one post that the riser and drill stem may be cut above the LMRP to provide a single discharge outlet."
That’s a crazy idea. ; )
Also, what is the riser burst pressure?
Petroleum, you said it was 1400psi?
http://www.oilstates.com/_filelib/FileCabinet/_R/G/_27G/Brochure...
Good pictures of a LMRP on page 7.
dsw93,
They will most likely not mess with cutting anything until the well is killed, the danger of making the situation worse is too great. They will put the cofferdams over the worse leaks and those are 800ft from the wellhead.
From the pictures they have put out, the cofferdams aren’t large enough to go over the BOP stack anyway.
As far as can be ascertained there are no accessible ports on the BOP stack, there may be test ports but they are most likely plugged and are not removable with the stack under pressure, if they could even be removed by an ROV. In either case they would be too small to be of any use for doing much more than a pressure port or injection of dispersants.
What pipe did BP cap? The one on the right side of that picture? Seems as thought BP isn’t afraid of getting the cutter out and installing valves. They must have done the calculations because their capped pipe hasn’t blown up yet.
I think any hope for fixing the BOP is gone. They’ve had engineers go from top to bottom on that thing for a week now looking for a fix and no results to show for it. We have to look elsewhere to solve this problem and not focus too much attention on a dead end street.
Hoodyz,
The pipe they capped was the broken drill pipe that was no longer connected to the well, it was just leaking oil from the old broken riser that is jammed into the seabed. It was basically a practice run for a live pipe down the road after the well is killed.
its probably the leak on the far right of the diagram, not connected to bop.
if something changes on bop/riser bp says its a risk of a 2.5million gallon/day leak
http://www.flickr.com/photos/uscgd8/4563035602/in/photostream/
some people a saying the containment unit slots down over the holes. others consider it to be a unit of four pillars with a funnel placed on top
hector160
They have pics of the cofferdams here.
http://www.rigzone.com/news/article.asp?hpf=1&a_id=92099
They have slots to lower over the leaking pipes.
thanks , that picture seems reasonable for the leak over riser end.
the one going over bop/riser/kink would be useful to see
if the dam sinks too far past the horizontal flaps thatd seem to risk kinking riser further and restricting riser end with mud lifting psi in whole system
hector160,
The leak coming out of the top of the riser is pretty small, they probably won’t mess with it, the risk of damaging the already over stressed riser is too great.
The coffer dams aren’t that heavy and the top half will be full of buoyant oil, and they also know the seabed conditions in the area, that’s why they put the mud flaps on at the height they did. Plus if it looks like they are sinking they can just pick up on the drill pipe they are attached to.
Posted this on another, less technical forum…
http://www.chron.com/disp/story.mpl/business/6991278.html
They’re really thinking this one out as hard as they can. Too bad they didn’t think of something like this before the accident. Ixtoc, almost exactly the same situation (BOP jammed with drill equipment) happened back in 1979.
The BOP is partially closed because it was activated.
Which is why I find the blathering by Bobby Kennedy and Mike Papantonio about the Norwegian acoustic option so annoying. It’s arguably not better (can be used maliciously, for example, to cause false well shutdowns) and in this case, wouldn’t have helped.
It will help to discredit progressives who let themselves get overly worked up over this single issue. There is a lot of meat available for reform of the drilling industry.
For one thing, things like these cofferdams should be prebuilt and staged for fast deployment. Just like the oil booms and dispersant stocks–which turned out to be highly useful.
And now that we’ve seen this situation of the BOP failure caused by well debris repeated (95% certain) we need to have a complete action plan for deepwater wells in case it happens again.
And everything we would use has to be either prebuilt or pre-installed. No more of this two weeks to figure out there is a problem and then start figuring out what to do about it.
That bitching aside, the response of the Coast Guard and also British Petroleum (once the accident actually happened) has been extremely impressive, IMHO.
The Gulf might just survive this.
Horizon 37 so help me out . the rams are fully extended but the shears did not make it to the other side ? I understand the the fluid displaced was the proper amount . But if the shears would have went to the extended point wouldnt the bore be clear or sheared ?
According to news reports, the relief well is being drilled by the Development Driller III and the coffer dam will be connected to the T/O Discoverer Enterprise. The Discover Enterprise is a dual-activity platform, so will they immediately begin drilling off its second table or hold the second relief well in standby?
The shears normally meet in the middle. There has being leaks in the hydrallic system so perhaps an accurate assessment of closure is uncalculatable. The piston seals may have lost integrity from contaminations
Accoring to Bp hydrallic leaks have now being sealed but id assume composition of fluids/contaminants in line etc will be imprecise
Unsure what another kick would do
I agree on the fluid loss . Hopefully the contaminants havent made the rams seals. So BP is taking care of the hydrualic leaks cool.
The man makes some pretty bold statements, he’s a media hound.
There is nothing wrong with the BOPs there is something in the BOPs keeping them from closing, as said before it’s probably bent drill pipe that is preventing the pipe rams and annulars from closing.
Without closed rams, and a method to attach lines to the stack, a top down kill is not possible. Not to mention the added pressure of bullheading in kill mud could burst the kinked riser, that for all anyone knows could be 10psi from bursting right now.
Besides they pressure tested the casing before they started the operation, it tested fine, or they would not have proceeded with the P&A. One way leaks in liner tops are not unheard of I have dealt with 2 personally, and the only way to fix them is to perforate the liner below the liner hanger set a packer and squeeze cement upwards to seal the lap. It could be that this leak is not at the liner at all, but at a collapsed casing joint above it.
There are many things BP is not letting out, like for instance did they do a cement bond log on the liner? For a production liner that is pretty much SOP, especially if its a temporary P&A.
Why didn’t they go ahead and perforate the production zone & test it? Then set retrievable or drillable bridge plugs in the liner & casing? This is also traditionally the way to go for a temporary P&A.
Why did they not spot heavy mud in the well BEFORE they swapped the riser to seawater? Even a rank amateur assistant derrickman would know that the well losing 5,000ft of mud in the riser on a deep water well would be inherently dangerous, it’s equivalent to pumping 5,000ft of mud out of a onshore well!!.
Why didn’t someone look at the choke manifold control panel to see if there was pressure under the blind rams BEFORE they opened them? Every rig I have ever been on does that, they also usually have pipe in the well and the pipe rams or annular closed on it BEFORE they open the blind rams, they also have a TIW valve or the kelly hooked up on top of the drill pipe.
hector,
The hydraulic fluid on subsea BOPS is antifreeze, more water won’t hurt them.
Shear rams, or pipe rams have to meet in the center otherwise they don’t fully stroke, the hydraulic pistons bottom out in their cylinders when the rams are in the middle and under the designed closure pressure, if one ram centers before the other one the one not centered just pushes harder.
dsw,
There are 2 relief wells being drilled, 1 by the DDIII and 1 by the DDII
the DDII spudded in yesterday morning. the DDIII Sunday morning.
"Every time we think we’re almost at the end of our options, our engineers keep coming up with new alternatives," BP communications boss John Curry told UpstreamOnline.
Charlie Holt, who heads BP drilling and completions operations in the US Gulf, said BP has repaired some leaks in the hydraulic systems of the BOP.
http://www.upstreamonline.com/live/article213922.ece?service=print
1st Cofferdam will be on site by morning, they expect 2 or 3 days to get it run in and the bugs worked out.
http://www.rigzone.com/news/article.asp?a_id=92865
Discoverer Enterprise is capable of dual hole operations within one derrick. It’s job on this operation will not be drilling. They have the pump and rigging that will recover the oil and separate the water. Consider it a contingency production platform.
Horizon
I think I share your aggravation. I listened to the MLevin show that Andre played James.
I think some steps and plugs where being skipped. Motorman or other designe would have been on the accumulator control. I am not familiar with DW ops at all. Where are the gauges and readouts for BOB pressure below the annular?
So Horizon 37 how does the the cylinder take all of the fluid and not get to where it s extended point ?
txgho1911,
There are several complete sets of instruments&controls for the BOPs, rig floor, toolpushers office, subsea engineers shack, and possibly rig control room/bridge on floaters. There are emergency shut ins at each survival craft station and other areas scattered around the rig. The ESDs also shut down the entire rig power grid except for emergency circuits and BOP controls and start the emergency generator, which will run the draw works and one mud pump and cementing unit if it’s electric. On Transocean rigs there only a hand full of folks allowed to use any of the controls, unless they have changed it it recent years, the toolpusher, driller if the toolpusher is incapacitated and the subsea engineer or his assistant if the driller and toolpusher are incapacitated, and the captain or barge master as a last option.
hdbob,
It doesn’t!! That’s how they know they didn’t close completely, since these systems run off of accumulators there is a non pressured reservoir for return fluid from the operators, this tank has sight glasses and level transmitters. When you activate an operator it takes pressurized fluid from the accumulators and closes a ram, when you open the ram it returns that fluid to the reservoir and the level goes up, an ROV can look at the sight glass and see how much fluid came back and tell within ozs if the operator ran a complete stroke.
Thank you, Horizon. I didn’t realize there was a third drilling ship on location (i.e., DDII, DDIII, and DE).
They actually are going to pump into the choke and kill line and do the top kill according to the Houston Chronicle article.
This is the procedure that has been preached in hear for awhile.
No one will not convince me of one thing in here and that is that this type of incident would be uncommon without some changes. I have drilled many deep wells in subsea and in South Texas and learned that kicks while running casing or waiting on cement are not one in a million occurences. Especially in oil based mud. Gas solubility is a complicated challenge and gas diffusivity is how it all begins. Liners are dangerous because the tops trap pressure that will leak once the top is disturbed by negative and positive testing. The liner top packer being standard now should remind us all how often they leak. I have read too many case histories on every wild well control companies’ books, in preparation for my own designs, and operations to believe kicks with tool joints in bad places are simply one in a million occurences. In Deepwater the amount of flowing gas is typically less than in dangerous places like South Texas simply because of the reservoirs being mostly oil wells subsea to this point in time. The deeper these wells go Deepwater the more gas kicks atop oil flows like this are lurking. This is simply because gas is always deeper. And the drilling has been targeting deeper, and deeper horizons. These occurences of world class gas zones will be coming more frequent with time.
I suspect the industry change to come will be shear ram technology, perhaps the permanent installation of an abrasive jet shear component. That idea became part of my thinking sense this incident.
I will be meeting with industry executives at an OTC related function tomorrow through the weekend and hope that the improvement ideas get implemented very soon, before government has to force them.
Petroleum Engineer1,
It seems you have put some thought into this, but drilling in ultra-deep water presents some very unique challenges, that occur in only one other place on earth, and that is high altitude mountain drilling. An analogy to deep water drilling would be drilling your average West Texas 15,000ft well with the rig floor on a 5,000 foot tower. Where if the rig was at ground level you would need 12ppg mud to balance the well, but 9.5ppg mud to balance it at the tower height, and if you use 12ppg mud at the tower height, you break down the formation. Can you see where this goes?
The rocket scientists at the various oil companies and drilling contractors are working on methods to lighten the riser mud while drilling, either by injecting base oil, air or other gas at the BOPs for oilbase mud or gelled water for water base mud, then running the returns though centrifuges and gas busters to return it to design weight and viscosity before going back to the pits. Myself I would pick gelled base oil to dilute oilbase mud because putting air or other gas in the mud creates way more problems than it fixes. They do this while maintaining the correct balance weight from the seabed down. It has the potential for some real screw-ups because of equipment malfunctions or inattentive operators, which BTW would mean adding more equipment to the rig and personnel to look after it. You would have to add 2 more full size mud pumps, because the riser circulation will have to be sufficient to dilute the mud as fast as it’s coming up, and all the added centrifuges and surge pit, shaker capacity and added material requirements, and of course adding yet another bolt on high pressure line to the riser and the changes in handling gear and flotation collars …. ad infinitum….. And if you should have to shut down for a kick or hang off for a storm with the rams closed, you’re back to square one with a column of heavy mud in the drill pipe.
The shear rams are a difficult fix too. You reach a point where the force needed to shear something exceeds the strength of the BOP body and the limitations of hydraulics and ram materials. Shearing 6" or so of tool steel as found in casing running tools, or 8" drill collar, etc., is a lot to ask of a hydraulic shear that would fit in the area of a subsea stack.
I am not an "oil man" but something is troubling me about the cofferdam and pipe to the surface. Doesn’t the oil contain a lot of gas, and isn’t that going to expand as it rises, like by a factor of 150?
The oil on the other hand is going to cool and get more viscous, no?
I don’t know how to do the maths but the situation looks something like an diver’s airlift with a lot of expansion in the top tens of metres that could create very low pressure in the pipe further down. What is the pipe made of and how great is its resistance to collapse?
old diver
surface seawater is going to be pumped down to keep oil temp up.
the gas will just be vented off by flare or collected
the drill pipe i think is being used as the collection conduit,its hollow steel and comes in a variety of sizes (thicksteel walled for deepsea ops)
hector160, OldDiver.
If you read the articles from the response center, they are using a double wall marine drilling riser, the oil will be up on the inside and heated water will be going down on the outside, they are also going to inject methanol into the cofferdam tops to prevent hydrate ice formation as the gas comes out of solution in the oil. The oil will never see daylight, it goes straight to an oil water separator and degasser, then to a storage tank, when that tank gets full, it is pumped to a lighter that will carry it to a shore terminal where it gets processed into the normal crude stream.
Link to Response Team Article:
http://www.deepwaterhorizonresponse.com/posted/2931/factsheet_su...
I suppose the 15%of the overall spill that BP says cant be collected by this system must relate to the leak by the kink where it was unsure if large/small hole. Leaving that to management by dispersion and relief well intervention or if that topkill trial does proceed
their estimates of the flow rate have had quite wide outer limits so the oil rate at surface i suppose should help make estimates of bop pressure values more accurate
I doubt if they will try the topkill, sometimes executives flap their jaws even when they don’t know the situation.
This situation is very very unstable, and they simply don’t have enough information about what is happening in the BOP stack. Even if they could find a way to tap into it to pump kill mud, it could make the situation much much worse. BP yesterday owned up to the fact that this well can produce up to 60,000 bbl/day I don’t think they want to let that monster loose, there’s not enough boom or dispersant on the planet to contain it.
The kink in the severely damaged riser could be all that is holding it back, and just the added pressure of bullheading in kill mud could force it to fail completely, leaving a totally uncontrolled flow from an 8-1/2" hole at 3,000psi or more.
A 60,000pbd spill would make the Exxon Valdez look like someone dropped some greasy french fries in the ocean.
Have you seen the Morgan Stanley report and interveiws? They eyewitnesses are stating that nobody survived the explosion that was near the controls. So Horizon 37 does the bop have check valves to hold the pressure in the accumlators so they wont bleed off ?
hdbob,
Yes even if the control umbilical burns in half it keeps the pressure, the hydraulic pressure on the BOPs is generated on the BOPs as long as the seawater pumps on the rig are running the pumps on the BOP keep running. This particular set up I believe has seawater powered pumps on it, although sometimes stuff gets replaced and not changed in the rig specs.
Now that there is a rig over the well maybe they will get the ROVs to hook up an umbilical and water line so they can charge the accumulators up again and also get a pressure reading in the stack.
Any Transocean or other operators want to explain to the layman?
Pneumatic controls on the accumulators is the sum total of my experience. You say seawater pumps are used on the DW BOP. What is used for stored energy to operate or how is water used?
One question above may not have been clearly answered. The gas in solution will as it expands traveling up the recovery/collection riser can separate and freeze while it decompresses. The methanol is supposed to keep the returns/output from freezing into a thick slurry. Is this expected to keep the gas in solution? I do not see that happening and expect everything will be going through a topside choke manifold.
Is this reasoning correct?
One hope I have is a few tons of pliable filler material dumped on top of the cutouts on this cofferdam. I am thinking sandbag and mudbags or bag weight material.
Have not seen any mention of what might be done to direct the oil up the recover/collection riser. I have seen a downhole jet pump used in utilitarian uses and this is also common on water wells with topside pumps. Sure that such encouragement would be required all the time but might help in drawing a slight under differential to maybe draw down from other soft or smaller leaking points that side of the pinched joints.
Anyone know what stage they are at with the caisson?
Is it in the water yet?
Also, what are they going to do if/when a storm/hurricane blows up? Under what conditions can the ship stay on station, and what happens if they have to leave?
‘Have not seen any mention of what might be done to direct the oil up the recover/collection riser."
That one is easy. Since oil is lighter than water, the vertical pipe is going to very quickly develop a strong pressure differential between the inlet and the surrounding water. With a mile of vertical pipe, the pressure will get quite high.
The problem will be controlling the oil’s drive to the surface, not trying to push it.
txgho1911,
Since this stack is rated to 10,000ft BSL there are no pneumatics on it, 5,000psi air is hard to come by.
A stack like the one on DH is electronic over hydraulic, some of the newer ones even have fiber optic stuff on them.
If I remember right the only direct control hydraulic lines from the surface are the ones to the LMRP connector, and the wellhead connector, and they are hard piped down the riser with the seawater lines for the hydraulic pumps. Everything else is electric signal down the control umbilical.
The pumps run off seawater from the surface with no return they exhaust at the seabed so all it takes for the surface pumps is like 3-400psi most of that is lost in line friction, they are low volume pump motors so it doesn’t take much. They charge the accumulator packs on the stack. I saw a pic of this stack somewhere last week, but I can’t find it now, it had six racks of 8 accumulators per rack they looked to be about 15ft tall, so they probably hold a lot of ethylene glycol mix.
The only accumulators on a modern semi or drillship I’ve seen are for the compensators, riser and guideline tensioners and one set for the diverter on top of the riser slip joint.
Some of the North Sea rigs have compensated deck cranes with their own accumulators, but I haven’t seen one in the Gulf, doesn’t mean there aren’t some though. I know of some Penrod rigs that have made the trip back and forth several times.
From what I can gather they may use some air lift jets part of the way up the riser to keep the oil moving, as to the methanol it should keep hydrates from forming slush or bergs on the way up, according to my figures the oil is probably around 200degF at the well head it probably cools a little on the way down the length of the riser to where it’s leaking. But gas expansion will also help it up the riser, as the oil gets lighter and lighter on the way up. It will probably pretty much be foam by the time it gets to the surface.
But remember this is a double wall riser and they will be pumping hot seawater down the outside annulus so it should keep the oil fairly warm on the way up. The way they have it figured that these cofferdams will sink in the muck on bottom to the skirts they have welded to the sides and there are 2 different size slots in them one to fit over drill pipe the other for riser.
And there will be a suction coming from the gas busters on the ship so that will help too.
Is there any more information as to why the platform sank?
From what is starting to come out in the news,
it looks like just after the folks got off,
somebody was definitely thinking about legal damage control.
Aside from this, I wonder what other sorts of damage control efforts were done in the early hours.
Maybe they recovered some logs that could help us understand what the state of things are below.