Comments on: Blowout: The Deepwater Horizon Disaster
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- A Goldie Locks Configuration to Stop the Gusher
Monday it was revealed (by accident perhaps) that BP is constructing 2000ft of 20" dia (approx) riser to put over the gusher. This is a good thing since 700ft of mud above the well will probably be needed to stop it cold (as the 700psi figure mentioned earlier would indicate and a mud density of 1psi per linear foot as opposed to sea water at .4psi per linear foot of depth).
Nothing was mentioned about the attachment method of the 2000ft riser to the bop but a welded flange at the bottom would be a closed system that could be bolted on. The Admiral implied that this might be a 7-10 day project.
This begs the question, since the top kill actually stopped the oil coming out it had to be act like a valve being closed. Since no leaks in the casing or formation were reported why not stick a valve on it and close it. If too much seeping occurred open it back up.
If the hydraulic gate valve (or xmas tree) were opened matching the flow rate to the recovery capacity would seem to be prudent. Granted the open (top hat with polygon guides or fasteners) system in use now exposes the oil to seawater creating a big hydrate problem but we have seen that can be mitigated in a variety of ways that can probably be improved on (given everyone starts to get more sleep).
Getting temperature readings from probes inside the pipe during unrestricted flow should help with hydrate phase calculations. There is precise data for pressure and temperature in the water column. Since the flow contains a large amount of methane knowing the precise rate of change in temperature at depth is needed to locate the point at which exposure to sea water would be safe (no-hydrate formation means no plugging in the recovery pipe running to the surface).
At the end of the 2000 ft 20" casing the pressure is 1200psi and seawater temperature of about 50 degrees. With the fluid moving at 2-3ft/s (2 a better fit for flow team rate) it should take about 30 minutes to reach the top.
Assuming the temperature T of the fluid is 10 degrees F and the rate of change of delta T is one degree per minute the temperature of the oil at the end of the 2000ft 20" casing should be about 40F (assuming a turbulent flow at the bottom but it is like to be more laminar at the top.
Thus 1200psi at 40degrees F indicates that salt water exposure at 2000ft above the Ocean floor would be hydrate free (methane remains in the gas phase). This is a rough approximation that should be refined using computer simulation (perhaps h = .15 for 50 wt oil).
All this points to a Goldie Locks configuration where the down hole pressure is adjustable, the valve might be completely closed in the advent of a hurricane, oil and gas capture free of hydrate formation and a casing above the bop about three times higher (2100ft) than that required for mud to equalize the pressure (700psi from the mud and 2000 psi from the water column depth of 5,000 ft).
BP indicated that an FSPO (Floating Production[4] Storage and Offloading) and FSO (Floating Offloading Vessel) configuration coming that can handle up to 85,000b/d.
Refs
[4].pe.tamu.edu/barrufet/public_html/PETE310/Labs/pdf/Lab%208%20-%20Hydrates.pdf - Reply to this comment
- Some Complicating Issues
A.) The above assumes the oil coming out of the bop has no hydrates (all gas). This may not be true and could change at any time and that might require a different strategy (if it was mostly hydrate coming out keeping it cold under pressure until reaching the FSPO would seem to make more sense). This may be the case with the Shell Platform off Brazil, which is a mile under the ocean and reportedly handling about 100Kb/d of oil and 50mcf of methane (not sure about the gas, its not as profitable as the oil, conversion to LNG is expensive and sadly transportation of hydrate is considered to not economically feasible).
All this could have been factored in already but there appears to be no way of knowing at the moment.
B.) The pipe for the 2000ft casing (briefly shown) appeared to be green and recycled, fine as log as it passes Magnetic flux and/or Ultrasonic NDE (Non-Destructive Examination testing. This is a cheap but perhaps practical choice as this pipe may likely end up full of cement.
What looks painful is that they appear to be bolting 2-3ft sections of riser together on the platform. If assembled into sections easy to handle (20-40ft?) before reaching the platform it might speed up the construction of the 2000ft lower marine section with flotation (and methanol injection, insulation, pipe warming, etc. to suppress hydrate formation if exposure to sea water creates hydrates).
C.) Hydrates, As mentioned before one mile down the Seawater Temperature is 40F degrees (4C), the pressure is about 2000psi (12Mpa). But the temperature of the oil coming out of the BOP is unknown. [1]
One might assume that it is very cold having gone through a pressure change of (12,000 to 2,000) == 10,000psi delta P. However, this is a fluid so that theory seems counter intuitive (no big change in volume). It started out between 200-400 degrees and went through two miles of rock, sand and mud at about 2-3mph after which it goes through the bop at 2700 psi and loves to make lots of hydrate (requiring a very cold temperature at that pressure)
Qualitatively we know that hydrates from quickly at the bottom due to all the problems we have seen.
At 1000 ft the annual h2o temperature is 50 degrees [1] and (1000 * .4 ==) 400psi [2]
At 3000ft the h20 temperature is 40 degrees (278K) and remains almost constant to the sea floor.
There is a bend in the Hydrate/Temperature curve around 40F degrees (278K) and 400psi (2.8 Mpa) where Methane Hydrate (a clathrate) can change state from a solid to a gas and consume 150 times more volume in the process.
At 3000 ft the psi becomes about 1200psi (8.3Mpa) and 55F degrees (286K) making for a volatile state change from hydrate (if there is any) to gas with a volume 150 times that of the solid.
So if we have a 2,000ft riser from the bottom of the floor (3000 ft from the surface) it would seem at first glance that we would have a 10 degree margin of safety.
But due to the fact we do not know the temperature of the oil at 5,000ft that readily created hydrates (probably no more than 0 - 30F degrees to leverage the ice crystal surface effect per Durham et. al.) [3]
Ref
[1] en.wikipedia.org/wiki/File:Methane_Hydrate_phase_diagram.jpg
[2] searchanddiscovery.net/documents/2007/07013forrest/images/03.htm
[3] llnl.gov/str/Durham.html - Reply to this comment
- Configuration Management Issues (Preliminary)
The barrels per day (worst case) has been described in the media as 100K b/d according to internal BP documents. We are now (60+ days) finally approaching the realm of reality (day one no spill, then a few days latter maybe a few gallons and so on). Its time to take a different tack, maybe because the CEO is (of all things) a mariner. What an affront to retirees that hold shares of BP stock in the US and GB.
"The US government does not have the expertise to solve this event." O.K.
However, the US government is compelled by law to manage the event effectively. The US government has managed work at an Ocean Depth of 16,000ft and manipulating loads in the hundreds (if not thousands) of tons previously [1]. The risk management on that historic project included the possibility of a Nuclear Reactor that may have melted down and really dangerous explosives (ICBMs with Nuclear Warheads).
What is objectionable about this "plugging the hole project" is that we keep seeing Rube Goldberg solutions that waste time and money. The only constructive thing so far is has been the cutting off of the riser and the recovery of a small fraction of oil and hydrates gushing from the well plus (maybe) two minutes of almost HD video worthy of some crude analysis (no pun intended).
All the Engineer in Chief wants to see is a generic petrol-industry patch that will capture all of the oil and a redundancy put into place that may assist the last option (bottom kill). Nothing more complex than running a piece of approximately 20"API SPEC 6 pipe to the surface with an API SPEC 6 flange on the lower end (to bolt on the top of the bop) and an API SPEC 6 hydraulic gate valve (xmas tree) at the surface on the platform.
Maybe we could suppose that the "Plan" might include a hose to fill up tankers with that 200K barrels a day the Industry said it could handle. Perhaps a ASME Pressure Vessel Boiler (Methane Fired) with Power Plant and Pump to circulate hot seawater around a closed system pipe running down to the bop and back to the platform, heating the insulated 20" pipe so that a 20" hydrate plug does not form (maybe this could be thrown in for good measure - cost should not be an issue under these circumstances).
This is intended to be a simple solution that will work at any depth with a good design (10,000ft and at pressures of 20Kpsi since the global industry is going there anyway).
When bottom kill starts the velocity of the fluid from the formation may be to fast for the mud to equalize unless it has an extra margin of error (up to 5,000 feet of 20" pipe from bop to platform - as the original system design called out).
The BP CEO is assuming 12,000psi at the reservoir and we know (according to the bop gauge) 2000 - 2700 = 700 psi on the fluid after the bop. Depending on the psi/ft of the bottom kill mud, Give us a really good margin of error (lots of extra pipe above the bop to equalize this monster).
This does not account for kicks from a formation with a fluid temperature variation of 200 to 400 degrees and may contain 5% to 50% hydrate or gas at any given time.
This is nothing more than trying to put back something that approximates the original design. Keep it Simple and Safe.
The tricky part will be to not snap off the bent stem under the flange of the bop because a lack of flotation gear on the 20" pipe, OR not close the valve so much that the casing and formation fracture anymore than they have already.
Hopefully to mud will stop the flow and cement pumped in without any problems.
Putting a cap on to contain more oil is fine, but pumping mud and cement would seem to have the best chance of working if it is done with as much of the original well design as possible in place.
Good Luck and God Bless.
Notes
[1] en.wikipedia.org/wiki/Project_Azorian - Reply to this comment
- The Third Order Approximation...
Putting my Imaging Analyst hat on I took as many screen shots of the HD video as possible during one-second intervals. The AP web version seems to be the best but its still highly compressed. There are two views, one from the crushed 6" pipe that is laminar (jet like) flow and just about impossible to measure because perturbations on the outer surface hide inner details.
We can say that it seems to be coming out a lot faster (as expected from a pinched pipe) But the opening its opening is probably only ten square inches). It is a lighter brown color and takes up a lot more volume as it moves away from the source.
The much darker flow coming out of the 20" pipe is appears moderately turbulent throughout the column and can be measured in inches per second based on shapes that span a few frames and come and go. It appears to be traveling at about 34" per second with (arguably) a volumetric diameter of 23".
Buy drawing a line across the 20" opening of the upper flange (on the captured images) that is 23" long and then draw a rectangle with a height of about 1.5 times the width which is 34" we now have the 2D outline of what we call a 55 gallon steel drum in the USA.
This is not an engineering analysis by any means but we can say conservatively that MORE than 50 gallons would be put in a 55-gallon steel drum in one second based on a sequence of images (ranging between 6 and 10 images per second - the real data set will have at least 30 frames per second).
So how many of these drums could be filled in 24 hours?
(60 seconds) x (60 minutes) x (24 hours) == 86,400
What is the 5-bolt solution for stopping the flow ?
Take off the 5 bolts holding the upper flange in place; replace it with a blank flange header (no hole) and torque down the five bolts (probably rated at over 1.5 million pounds of tensile strength each).
A blank header flange is not being advocated here, but it is a fundamental capability of any operation using pipe.
How many gallons a day, minimum? 86,400 x 50 == 4.3 million - Reply to this comment
- The Second Order Approximation...
The casing may be damaged (or even substandard). No exploratory well meters 0-20Kpsi, 20k-200kpsi (one on the BOP seemed to go up to 3500psi, seemed to read 2700psi but never got any confirmation). Model of the formation is not being released (seismic, well logs, sensor data, chemical composition, temperature, pressure, FMEA, etc). Assurance that
there are no geothermal vents in the formation (along with large Hydrate deposits) would reduce the fear factor (a lot).
In order to mitigate casing/formation failure venting (via release into ocean) or transport of oil to surface (and recovery) required to reduce pressure. To much pressure drop will drive temperature drop and encourage Hydrate formation (making flow control difficult if not impossible risking casing failure).
Adding the following improvements to this approximation would be:
1.) One or more 5000ft of six inch pipe risers after the main valve (flotation needed to reduce stress on bent bop below flange).
2.) Extensive Heat Trace and Insulation on Main Valve and Riser(s)
to prevent Hydrate formation.
3.) Leaving site during a Hurricane is not an option unless excess
fluid is dumped in gulf (a really bad idea). Another Deep Horizon
Rig (Storm Proof) is needed for excess fluid coming to surface (and off loading to tankers).
4.) Avoid untested techniques, stop spilling, period. - Reply to this comment
- Let me make this as simple as possible.
At the moment BP has chopped off all the pipe[3](CHEERS!!!) to the upper and lower flange on top of the bop. However that yellow cylinder with triangular like polygons is going to fail if my model of poking a hole in a giant pressure vessel boiler is correct (the pressure may not be from the crust alone but also from geothermal vents [1]).
The ROV operator's are getting better every day and can probably anchor one arm on the bop frame while placing the 3-6ft torque wrench on the top of the bolt. A sibling ROV (they do seem to have personalities) will anchor one arm on the BOP while placing a wrench with the other arm on the appropriate Nut on the bottom side of the lower flange.
Furthermore we should expect jets to blow the clouds out of the area without having to bother the principle ROVs doing the work.
Once the Top Flange is removed we want to replace it with a new flange that has a three foot long piece of pipe welded to the flange on one side and the other to a valve (tested, known to work, welds NDE tested and inspected).
Obviously the specification of Flange, Pipe and Valve need to be validated, verified and certified as to fitness and service ratings.
This assembly is then lowered into the depths (the valve is open) placed in position (on top of the lower flange). The arduous task of placing nuts and bolts in position and installing (using the appropriate torque value and pattern) can then begin.
At this point the jet should be able to be valved off [2].
We could use 5K feet of pipe to take it to the surface put the metal between the flange and bop has been bent (the collapse of one mile of riser) so its not all that strong.
The existing bop could also come apart in which case a new one might be installed, but the strength of the pipe to bop interface is unknown (not being bent or cracked would be good).
Notes
-----
[1] My model for this thing is the International Pressure Vessel Boiler Code and my hope is that drilling deeper will someday make geothermal base line energy a reality. I think that drilling technology is getting us closer all the time, the pipe would not bring up oil, gas or water but fluid heated to about 600 degrees to drive turbines.
[2] If no valve exists the valve off this hole we poked in a giant pressure cooker (which I really doubt considering the monsters used in megawatt power stations) a spear could be fabricated that would fit inside the inner diameter of the pipe (with plenty of slop) that could be lowered into the super hydro jet until it is all but stopped. This would give us a psi value. Inconel, Tungsten, Depleted Uranium might work. The spear needs a threaded back-end so weight can be added. Starting out at 50 tons sounds about right. Deconstruction of the inner pipe might be required as well as increasing the casing thickness.
[3] Cutting off existing pipe smoothly is something that could have been modeled in a parking lot (in Houston) and then in a shallow pool before being tried at depth on site. Its the old tried and true way of doing things, testing is a good thing. - Reply to this comment
- I've got some A.S.M.E. experience. There is a flange just below where they made the last cut (very top of the bop). Replacing the top flange (by undoing a number of bolts and nuts) should not be that difficult if we put on our engineering hats. Replacing the top flange with a prefab valve installed (or even 5000 ft of pipe) would not seem to be that difficult compared to all the things tried so far. Industrial pipe, tool and die, torque wrenches, safety wire, gaskets, NDE and good metallurgy is proven technology, some still sits on the moon (I have a little spacecraft experience also).
The ROV pictures show a really big cloud obscuring everything, so having some jets to move the cloud over (to see the flange) might help.
That gamma ray machine might also give mission control enough vision
to get at the flange bolts on and off. If all else fails the can be ground off (oh, I forgot to mention some linear accelerator experience in another life).
Various Alignment tools (pipe inserts, guide rods through sloppy bolt
holes) would seem to make things a little easier. The mass of whatever
is welded to that top replacement flange should be enough to keep it
from moving around. If not take a cutting torch to the top of that
100 (or was it 50) ton box to remove it. Then add whatever is needed to guide the replacement top flange assembly in place - it might even be another bop.
(Rocket, Nuclear, Industrial, etc.) Scientists can solve just about any problem that comes up during operations (at least the ones I've worked with). Just be thankful that this is not a Nuclear Reactor meltdown (the emergency core cooling system is interesting but that's a discussion for another day, geothermal seems better but does not get mentioned much).
So Houston, sit back, use the brains GOD gave you, and please plug the hole. The lunar rover was sweet, so show us what you got. - Reply to this comment
- Article from Las Vegas Review Journal:
http://www.lvrj.com/news/exxon-valdez-oil-risks-spur-warning-for-gulf-cleanup-crews-93258964.html
More on the Subject:
The workers who are cleaning up the oil in the Gulf need to be aware of the chemicals that will be used for the cleaning. I am one of the 11,000+ cleanup workers from the Exxon Valdez oil spill, who is suffering from health issues from that toxic cleanup, without compensation from Exxon.
My name is Merle Savage; a female general foreman during the EVOS beach cleanup in 1989, which turned into 21 years of extensive health deterioration for me, and many other workers. Dr. Riki Ott visited me in 2007 to explain about the toxic spraying on the beaches. She also informed me that Exxon's medical records and the reports that surfaced in litigation brought by sick workers in 1994, had been sealed from the public, making it impossible to hold Exxon responsible for their actions.
http://www.rikiott.com
Dr. Riki Ott has devoted her life to taking control from corporations and giving it back to We The People. If corporations continue to control our legal system, then We The People become victims. http://www.MovetoAmend.org
Dr. Riki Ott has written two books; Sound Truth & Corporate Myth$ and Not One Drop. Dr. Ott has investigated and studied the oil spill spraying, and quotes numerous reports in her books, on the toxic chemicals that were used during the 1989 Prince William Sound oily beach cleanup. Black Wave the Film is based on Not One Drop, with interviews of EVOS victims; my interview was featured in the section; Like a War Zone.
http://www.blackwavethefilm.com
Exxon developed the toxic spraying; OSHA, the Coast Guard, and the state of Alaska authorized the procedure; VECO and other Exxon contractors implemented it. Beach crews breathed in crude oil that splashed off the rocks and into the air -- the toxic exposure turned into chronic breathing conditions and central nervous system problems, along with other massive health issues. Some of the illnesses include neurological impairment, chronic respiratory disease, leukemia, lymphoma, brain tumors, liver damage, and blood disease.
http://video.google.com/videoplay?docid=5632208859935499100
My web site is devoted to searching for EVOS cleanup workers who were exposed to the toxic spraying, and are suffering from the same illnesses that I have. Our summer employment turned into a death sentence for many -- and a life of unending medical conditions for the rest of us.
http://www.silenceinthesound.com/stories.shtml
http://www.silenceinthesound.com/gallery.shtml - Reply to this comment
- What I don't get is, "Where's the outrage?" I feel like we're back in the Bush/Cheney years when this most of our nation's citizens were comatose because the White House was surreal.
Why don't we shut operations on the Atlantis Oil rig owned by BP - and any others that BP is opeating off America's shores until they have complete and authentic safety inspections??? Greed!!! We always come back to that most insidious of the seven deadly sins. Obama, and he is my President, should grab this bull by the horns and make Harry Truman's statement, "The buck stops here!" mean a lot more than it did in Truman's era.
I think we should shut down every rig operated by Transocean, or built and maintained with Halliburton products until they all pass rigorous safety inspections. But then I'm just an ordinary American citizen who's doesn't give a hoot about being elected or re-elected to any government seat. Where's the outrage in our Senate and House of Representatives?? Why isn't this oil rig explosion and its consequences thus far the main topic of discussion?? We can't undo the current disaster (and we'll be damn lucky if this isn't the worst ecological event in our lifetimes,) but we just might be able to prevent a de je vu nightmare from happening in the near future.
The Pols and Wall Street need to get that the American public is fed up and sickened by the unabashed greed that is destroying this nation and perhaps the entire world as we knew it. - Reply to this comment
- this was such a terrible accident. btw check out this politics site i think u guys might like it http://www.ThePartisanDialogues.com
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