use gas lift pump on BP Macondo blowout?
use gas lift pump on BP Macondo blowout?
(OP)
To capture the leaking oil and gas until it has been stopped, would a gas lift pump work? There is about 40% methane by mass in the leak. This high percentage of gas would create a very powerful gas lift.
Direct the leak -that is, after the oil/gas has left the wellhead and is in the water at the 5000 foot depth (in other words, I am not suggesting using gas lift in the well itself) - into the open bottom end of a pipe running down to the leak from a salvage vessel.
Once this flow starts moving up the pipe, the highly pressurized methane will continuously expand because the pressure above the mixture is constantly falling. This will reduce the average density of the mixture in the pipe. At steady state flow, it will be much lower than the density of the seawater outside of the pipe.
It would be a giant chimney but with a much greater driving force than if the fluids were gases only, because of the much greater densities and the much greater difference in those densities. If the average density in the pipe is 4/5 that of seawater, the driving force at the bottom of the pipe would be more than 400 psi.
The oil/gas/water mixture will exit the pipe at high velocity at the salvage vessel, perfect for separating the liquid from the gas in a cyclone.
No outside power needed, equipment far simpler and cheaper than what they have been trying.
I know that word - CLATHRATES. They will plug up the flow! But will they, with 400 psi driving it? And if they are a problem, do what they are doing with tophat and put some methanol into it, or some warm water. Not hard when we are looking at the complete destruction of marine life in the Gulf of Mexico and the consequences of that.
Direct the leak -that is, after the oil/gas has left the wellhead and is in the water at the 5000 foot depth (in other words, I am not suggesting using gas lift in the well itself) - into the open bottom end of a pipe running down to the leak from a salvage vessel.
Once this flow starts moving up the pipe, the highly pressurized methane will continuously expand because the pressure above the mixture is constantly falling. This will reduce the average density of the mixture in the pipe. At steady state flow, it will be much lower than the density of the seawater outside of the pipe.
It would be a giant chimney but with a much greater driving force than if the fluids were gases only, because of the much greater densities and the much greater difference in those densities. If the average density in the pipe is 4/5 that of seawater, the driving force at the bottom of the pipe would be more than 400 psi.
The oil/gas/water mixture will exit the pipe at high velocity at the salvage vessel, perfect for separating the liquid from the gas in a cyclone.
No outside power needed, equipment far simpler and cheaper than what they have been trying.
I know that word - CLATHRATES. They will plug up the flow! But will they, with 400 psi driving it? And if they are a problem, do what they are doing with tophat and put some methanol into it, or some warm water. Not hard when we are looking at the complete destruction of marine life in the Gulf of Mexico and the consequences of that.





RE: use gas lift pump on BP Macondo blowout?
David
RE: use gas lift pump on BP Macondo blowout?
"Your submission has been reviewed for its technical merits. Unfortunately, the team has determined that your idea cannot be applied under the very challenging and specific operating conditions we face. All of us on the Horizon Support Team appreciate your thoughts and efforts."
Of course they don't have time to explain why they think it wouldn't work. That is why I am asking for comments on this site.
There is some discussion of the gas lift effect on the Oil Drum today (June 4), although not in response to any of my posts there on the subject.
It is taken for granted at the Oil Drum that clathrate formation must be prevented. Therefore seawater cannot be allowed to enter the flow.
The Top Hat attempt now underway apparently does rely on gas lift to move the oil/gas. On Oil Drum there is speculation about unstable flow in the pipe leading from Top Hat to the salvage vessel due to unpredictable behavior of the methane as it expands, which requires extreme caution as the flow up the pipe is allowed to increase.
My main question is why there cannot be some seawater allowed into the flow. It seems to me that any clathrates would be swept along fast enough to prevent plugging. If some seawater could be allowed, there would be no need for a seal on Top Hat, or even a top hat. It could simply be an open pipe just above the leak, taking in the oil and gas and the minimum possible amount of seawater. All that cutting of the BOP and delay could have been avoided. The pipe could have been sent down almost as soon as the leak began.
IF the method works. Why didn't we know this already? Because the oil industry - and many others - have been allowed to regulate themselves.
RE: use gas lift pump on BP Macondo blowout?
There will be a gas lift effect from the methane in the flow, (but this well doesn't depend upon gas lift to flow as the reservoir pressure is more than enough to flow to surface- that's why it's blowing out!) but speaking as someone who has designed gas lift systems, the amount of gas injected into the liquid stream does have to be calculated pretty closely to stop a well from slugging. This isn't a designed system, so there will be concerns about the flow regime in the riser as they ramp up the flow up the riser.
RE: use gas lift pump on BP Macondo blowout?
Just from the internet, since I am not versed in this subject, one way to remove clathrates is to reduce the pressure and increase the temperature. Both of these processes occur naturally as the flow moves up the pipe at the Macondo blowout.
In the arrangement I am suggesting, to get the flow started and avoid clathrate plugging until it is no longer possible (ie., when the flow is further up the pipe, but then I am assuming this would be the case), warm water and methanol injection might be enough. I believe they have done both at Macondo, but details of application, temperature, flow etc, are not available so far as I know. In any case, their object is to avoid seawater influx at all costs, and the warm water and methanol is not being used in any proposed system similar to the one I am suggesting.
If methanol injection is expensive, in this case the expense would be negligible compared to the damage that could be avoided.
I realize that the current Top Hat is using pressure from the well and not relying on gas lift, although there must be considerable gas lift occurring also. My approach is to let the well leak and avoid stressing the BOP and piping, then collect the leak after it is in the water.
Hope you can comment further.
RE: use gas lift pump on BP Macondo blowout?
Regarding BP's expertise in clathrate formation, I wonder what the justification was for the original 100 ton containment dome. It plugged with clathrates almost immediately. If BP knew this would happen, then the effort was for public relations only.
If they weren't sure that it would happen, and thought that it was worth a try, maybe they don't know as much about clathrates as we might suppose. In that case, maybe my suggestion was dismissed for no good reason.
Possibly it was not even examined, and the reply I received was a standard form sent by email robot. Experience tends to erode one's trusting nature.
RE: use gas lift pump on BP Macondo blowout?
With a few thousand PSI rising to possibly 15,000 PSI if the leak is restricted, and the specific gravity of being less than water anyway, why do we want a gas lift? I we use air for the gas lift we can have the excitment of an explosive mixture instead of a flamable gas reaching the flare stack.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
Two days are proposed to install the new cap. Thats an estimated 840,000*2= 1.68 mil gallons of oil being leaked in 2 days. Is it worth the extra 50-100,000 gallons per day collected?
IMO, if whats happening now is working, tweak the current idea, but its pointless trying something completely different unless the cap hits a "snag", or there is a 99% chance of success. Good luck with the latter.
"Scientists dream about doing great things. Engineers do them." -James Michener
RE: use gas lift pump on BP Macondo blowout?
Why am I proposing gas lift? Because it would take the strain off of the BOP and well piping/casing. There is tremendous uncertainty about the condition of this equipment. That is the main reason they are going so slowly in raising the flow in the current top hat, and nearly half of the oil is still leaking with this arrangement.
If the leak is allowed to enter the seawater and could be collected as I suggest, then there is no connection to the wellhead and no need to go through the tremendous and time consuming effort of trying to attach some kind of collector to the wellhead. The pressure and other conditions in the seawater at the point of the leak are exactly known and calculations would be on a reliable basis.
If the method works, it might capture all of the oil and gas along with some seawater. It could be used at future blowouts of this kind, tested and ready to go. If it works, the oil companies ought to be required to have the equipment in place at all times, in case of a blowout. We have learned that no such method is available yet.
RE: use gas lift pump on BP Macondo blowout?
Not true, check my numbers.
And also, they quit using the term top hat with the last 2 failed attempts. This is just a cap, with no flat bottom. This is just me being picky. To all their own.
___ ___
| | instead of _| |_
With that being said, I agree with your statement, if done correctly it could be very beneficial.
"Scientists dream about doing great things. Engineers do them." -James Michener
RE: use gas lift pump on BP Macondo blowout?
Can't figure out what "instead of" means in your second post.
Top hat may be old hat, but I believe we know what I meant by it. Are they calling it a cap now?
RE: use gas lift pump on BP Macondo blowout?
"Scientists dream about doing great things. Engineers do them." -James Michener
RE: use gas lift pump on BP Macondo blowout?
As I understand it, they are concerned that the casing and cementing have been compromized. If they stop the leak by closing the BOP completely, the concern is that the cementing or the casing may fail from the increased back pressure.
A subsea casing rupture or a casing lift that also lifts the BOP may cause subsurface leaks so that instead of the leaking oil escaping from one pipe where there is a chance of collecting most of it, they may have oil seeping up through the sea floor over a very wide area. Worse, this oil flow may not be affected or reduced by the partially closed BOP as it is now.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
There is technology available to control oil well kicks and blow-outs. It has probably been in use for over 50 years.
Called BLOW OUT PREVENTERS.
Most operators will not drill if the BOP is in bad order.
Let's look at the sequence of events.
1> The BOP was damaged and not repaired about a month earlier.
2> They knew that they had a hydraulic leak in the BOP but continued working
3> They knew that the pressure was down in the BOP hydraulic system and continued working.
4> When the cementing crew came onboard, they did not know and were not told that the BOP was in bad order.
5>A bad decision was made to replace the drilling mud with sea water to save money.
6> The well kicked. The kick may not have happened or may have been less severe had the mud been in place providing almost twice the back pressure of the sea water.
7> The cementing crew saw the kick coming and reacted in the proper manner to control it. They activated the annular device to contain the kick.
There was no annular device. It had been destroyed and not replaced.
8> There is a good chance that the activation of the missing annular wasted more hydraulic fluid and pressure.
8> The shears were eventually deployed. They did not complete their stroke. Possibly due to the depleted hydraulic oil supply or due to the reduced reserve operating pressure. Possibly both. Possibly the BOP was under engineered for the application.
bp can't handle the existing technology. How much more technology do you want to see them mess up??
This is not a technology frailure. There is enough techology and enough people that know how to use it safely. Just not in the bp chain of command.
Bill
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"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
waross, roger that, BP has committed many sins with this job and heretofore. As someone said on the Oil Drum, he didn't want to mention any names but a certain oil company seems to be experiencing the laws of karma.
Good clarification about the BOP, it is the underground piping they are most worried about. However, I have read that there is a significant failure rate with BOPs, something like 25%, even when they are not mistreated as BP apparently did this one. I would provide some kind of a link for this statement, but am having internet connection trouble. It is a wonder I got back to this site.
On the Macondo BOP, there is speculation that the shears happened to be over a joint in the piping. Shears are not designed to cut through a coupling, so it might not have helped if the hydraulics had been working. In response to this blowout, there is a proposal to require two sets of shears on the BOP, four feet apart, so that at least one of them will miss the coupling.
RE: use gas lift pump on BP Macondo blowout?
bp's public relations to the contrary this is not a "One in a million" occurance. Kicks are common in some formations and areas and are routinely contained. What is more unlikely is the cavalier way that standard safety procedures were violated.
If the shears hit a joint, that would be less fluid and pressure for the second set of shears to close.
There are also sections that are designed to seal around the drill pipe.
The annular seal is the first response. I understand t6hat there are designs that will seal around a drill pipe, around a coupling, or seal a casing with no drill pipe in place.
But what it will not do is seal a well when it is in pieces on the mud screens.
The gate seal that has a profile and seals to close around a drill pipe is the second response.
Shearing the drill pipe is the last response.
Bill
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"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
As I mentioned above, if BP knew that clathrates would always plug up the pipe in these conditions no matter what, why did they try the first containment dome? If it was just PR to gain a little time, then the PR failed along with the dome.
If they thought that the dome might work, then either they are complete fools regarding clathrates, or they had some reason to be believe that the plugging could be prevented.
If so, then there should be a way to implement my idea.
As I mentioned in an earlier post, the BOP and well piping are left alone when using a separate pipe for the gas lift, and the big worries about damaging the well by attaching something to it are over.
They can collect all of the oil and gas after it has leaked until they can stop the leak. Not only that, the method would work in similar situations, which are bound to happen.
RE: use gas lift pump on BP Macondo blowout?
As I understand it, this started with a "Kick" and as I undestand that, a kick is a sudden unintended gas lift.
The challenge is to collect as much product as possible without including water in the mix. As I understand the dynamics, conditions are very good for the formation of clathrates and I suspect that the cooling caused by the expanding gas may lead to ice buildups as a further problem. I believe that at this point, it may be as well to leave well enough alone.
Perhaps the easiest way to effect a "Gas lift" would be to simply heat the cap and encourage the gas already present to expand and start the lift.
Trying to change the cap now to achieve a better seal is probably the most effective way to deal with the problem. Unfortunately the increased discharge during a change and the possibility of failure may result in a net loss in collection at the end of the month.
Once the oil has escaped, the collection difficulty increases enormously.
Your position and focus is to collect the escaping oil. My position is that the best solution is to collect as much as possible before it escapes.
Everyones problem is the Peter Principal as it applies to bp culture. I am sure that there are a lot of very good engineers working for bp. Unfortunately, when promotion time comes, the best engineers are often left doing the real work while the less productive are promoted. It ain't fair but that's life.
I may be wrong. There is so much information not available to the general public that engineering a solution is almost impossible.
What is the well pressure?
bp won't say.
What volume is leaking?
bp has prevented this from being determined. There was a team of scientists on route to measure the leakage rate with proven technology. They were turned around and the big lie started that measuring the rate of leakage was impossible.
Peter Principal and culture may have been responsible for this mess. (How do you spell hubris)
The engineers trying to solve this have the triple anchors of Peter Principal, culture and now, goverment interference. I think that they are doing as well as can be expected.
Bill
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"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
From the symptoms, I can only guess that the flow to the Discoverer Enterprise is flow-limited, choked, somehow. Has BP done the flow study to determine how much oil and gas the flowline can handle? What about the flare line? Is it operating at its sonic flow limit?
Seems to me that in order to properly design the flow system from the BOP Cap to the ship, BP would have first done an open-flow study of the well to realistically know what is the amount of oil and gas that is probably coming up from below. That would establish the required capacity of the Cap and its connecting line to the ship.
Surely BP did this. Surely BP didn't create a problem by designing a line and onboard flare and separator system that didn't have that capacity.
Are we missing something here?
RE: use gas lift pump on BP Macondo blowout?
junkcatcher, as I understand it from the Oil Drum, the cap and riser are delivering more flow than the processing equipment can handle, so yes, they apparently made some mistakes. And the captured oil flow is still less than the leaking oil flow. The way things are going, the reputation of engineers is going to be reduced to the lawyer level.
Also on Oil Drum, we are reminded that the work on the recovery vessels is very dangerous, especially because of the unpredictable flow rate and the constantly changing fractions of oil and gas. oceannomad said: "There is an old oilfield adage which I hold dear - Courage is proportional to the square of the distance away from the wellbore."
RE: use gas lift pump on BP Macondo blowout?
Dekker Inc., 1990.
An old book, but you can probably find some things in there to support your argument Windward.
"Scientists dream about doing great things. Engineers do them." -James Michener
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
1> The BOP was damaged and not repaired about a month earlier.
If this is teh suspencted damaged thte annular preventer, don't forget there are two annular preventers on a 15k BOP stack, (like the Deepwater Horizon had), so there's spare annular. And annular preventers are designed to cope with pipe being stripped through them. So maybe there was some damage to the elements on one of the annular preventers, but perhaps the rig crew had no reason to believe the annular preventer was compromised, and there's a spare one anyway?
2> They knew that they had a hydraulic leak in the BOP but continued working
Again, risk management- how big a leak? Did it compromise the functioning of the entire BOP stack or one of the invidiual preventers? As subsea hydraulic control systems vent to sea anyway when a preventer functions, the leak was probably not throught important
3> They knew that the pressure was down in the BOP hydraulic system and continued working.
Again, it's not a sealed system- it vents to sea. Provided sufficent pressure could be supplied from the surface accumulators and koomey unit pumps, perhaps it wasn't seen as an issue?
4> When the cementing crew came onboard, they did not know and were not told that the BOP was in bad order.
I fail to see why the cementers should be told this. I've never ever had a cementer ask about the condition of the BOP when they come to cement my wells
5>A bad decision was made to replace the drilling mud with sea water to save money.
No, no no no.
The riser was displaced to seawater in order to deliberately reduce the pressure inside the casing to below the reservoir pressure to do an inflow pressure test on the casing. At this point the casing was set & cemented and had had two sucessful positive pressure tests, so the casing appeared to be in good shape. I don't know the exact method of the inflow test, and possibly BP could have done it another way (close the BOP to isolate the riser & displace just the choke & kill lines to seawater?) but the principle of doing an inflow test on production casing is accepted.
6> The well kicked. The kick may not have happened or may have been less severe had the mud been in place providing almost twice the back pressure of the sea water.
Currently one of the ideas about the source of gas is a gas bubble formed behind the 9-5/8" x 7" production casing during the cementing operations, and the (pressure tested) casing hanger seal let go during the inflow test. If this is so, then the failure could have occured a couple of days later (they were in the process of suspending the well ready to go home), when teh riser would be displaced to seawater to recover it to surface. And in that scenario, there would have been no comminication with the BOP at all....
7> The cementing crew saw the kick coming and reacted in the proper manner to control it. They activated the annular device to contain the kick.
There was no annular device. It had been destroyed and not replaced.
I think you mean the driller.... I wouldn't expect the cementers to be anywhere near the BOP control panel. And perhaps the damaged annular preventer failed. But there's another backup annular preventer. And two pipe rams, designed to seal around the pipe. And a blind/ shear ram. why did all of the BOP preventers fail to close fully?
8> There is a good chance that the activation of the missing annular wasted more hydraulic fluid and pressure.
8> The shears were eventually deployed. They did not complete their stroke. Possibly due to the depleted hydraulic oil supply or due to the reduced reserve operating pressure. Possibly both. Possibly the BOP was under engineered for the application.
Or possibly because they didn't have time to space out to ensure there wasn't a tool joint across the shears? No shear ram anywhere an cut tool joints.....
There are lot of unknowns about this disaster.... why did the deadman switch fail, for example. But so far, we don't really know much at all, so I'm prepared to wait until the inquiry reports before blaming people and shouting about short cuts.
RE: use gas lift pump on BP Macondo blowout?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
The immediate job is to stop the blowout and deal with the damage. There were two posts on the Oil Drum yesterday that I investigated: Operation Sombrero and a show on Discovery Channel called "Disaster in the Gulf".
Operation Sombrero was an attempt to deal with the Ixtoc blowout in 1979. It was a gas lift pump, the subject of this thread. So far as I can tell, it worked. The best source of information on it that I can find is the book Offshore Pioneers: Brown and Root and the History of Offshore Oil and Gas. Google Books provides an excerpt, but just as it gets interesting, Google skips the important pages. If anyone can legally post the missing information, please take the time to do it:
htt
The Ixtoc well was in 150' of water in the Bay of Campeche, southern GOM. Compared to the DH situation, the water pressure was low and the temperature was high. In other words, Sombrero probably didn't have any problem with clathrate hydrates of natural gas. I hope no one will object if I continue to call them clathrates. At least it is short.
I believe it should be possible to deal with the clathrates at DH, so that a gas lift pump would work to capture all of the leaking oil and gas. I am still working on the idea, but my approach is to use the heat from the flared gas to heat the incoming seawater at the leak high enough to prevent clathrate formation. I have not yet been able to obtain a copy of the book that whammet noted above, but I have no doubt that it would provide all of the information needed to develop this idea.
Regarding the show on Discovery Channel, which I haven't seen yet, I was looking for information on it at their website and found this:
http:
It is something like a gas lift pump, although the inventor seems to be oblivious to the high concentration of natural gas in the DH blowout. He is relying on the density difference between oil and water.
The man is trying to patent this idea. I say it won't work because:
1. If the flow could be started, there would soon be enough pressure difference between the inside and outside of the plastic tube to collapse the tube.
2. He thinks that the oil will placidly collect on the surface for skimming. He doesn't mention the natural gas blowing up with it. I wouldn't want to be a skimmer on that operation.
RE: use gas lift pump on BP Macondo blowout?
1. Whether to do the inflow test as part of the suspension operation, with a cement stinger, or if to do with a dedicated work string with a check valve in it
2. the details of how to do the inflow test for example displace the riser to seawater with the drill pipe, or RIH with a mechanical packer, set just below the BOP, close the BOP displace the kill & choke lines to seawater, unset the packer.... I don't know the exact layout of the wellehad and BOP, so I don't know what methods they could have used.
3. or it could have been about something completely unrelated- a crew change flight being cancelled!
So far, we just don't know.
RE: use gas lift pump on BP Macondo blowout?
Some knowledgeable people now fear that the casing might deteriorate to the point where the blowout becomes uncontrollable. You understand the technical reasons for this better than I do, and I hope you will comment.
If this occurs, the only recourse left is to capture the oil after it leaks, as I am proposing with the gas lift pump. The main objection to this device is that methane hydrates would plug it up, because the water is cold and the pressure is high. There is chart of the conditions for the formation of methane hydrates at
htt
This chart indicates that these hydrates would form at the Deepwater BOP. I believe that the water is just a degree or two above freezing at the 5000' depth. It would have to be warmed to nearly 70F at that pressure to prevent clathrate formation. This might be accomplished by using the heat from the flared gas, or by injecting oxygen at the leak and causing a controlled fire in the flow.
The chart does not indicate how fast or how much clathrate would form. That is also critical information for my proposal. Maybe they wouldn't form fast enough to plug the riser, if it was big enough. One poster on the Oil Drum contributed the very interesting point that the hole in the original Top Hat, or 100 ton containment dome - which reportedly failed because of clathrate pluggage - was only 1" in diameter, even though it led to a riser that was at least 6":
http://www.theoildrum.com/node/6588#comment-647701
It certainly appears that they put a 1" orifice in this device. What do you think about this?
RE: use gas lift pump on BP Macondo blowout?
Courts will decide if there was criminal activity. If there was, then that activity was performed by PEOPLE. Individuals with a physical being and free will. It is sloppy, lazy language to assign human conditions to corporations. But damn, isn't it easy. You can say "BP is a criminal organization" and in one fell swoop you can condemn 110,000 employees, a dozen board members, and many millions of stockholders. You know, those employees, board members, and stockholders are just folks trying to make a living. The vast majority of them are law abiding citizens who pay their taxes and participate in the community. Labeling us (I'm a stockholder of bp, I retired from the company, and my son currently works for them) as criminals is grossly inappropriate and I am deeply offended.
David
RE: use gas lift pump on BP Macondo blowout?
I don't know if good industry practise or BP procedures or Transocean procedures were followed. What I have seen in terms of the Daily Drilling Report and the mud log released to the US Senate doesn't indicate the awful well design, poor decision making and piss poor supervision that resulted in the Montara blowout off Australia a year ago, but we havn't seen all of the details of this incident yet.
Gas hydrates form almost instantly, in the vidoes I've seen. The easiest way to stop them is to eliminate water, or to inject glycol or methanol, which is much easier than heating the well fluids up from about 4° C to 20° C or so.
I don't know the details of the original containement dome, I'm afraid. A 1" orifice would see pretty small.... I am pretty disappointed that no-one remembered about gas hydrates and thought to put a chemical injection line on it, but I guess that's what happens when you are frantically designing and fabricating the thing ASAP.
I wouldn't put the for this on BP, but on the entire oil industry that has been drilling & producing in the deep and ultra deepwater for 20 years and has developed some astounding technology to do it- DP drill rigs, riser booster pumps, Steel Catenary Risers, Free standing risers, Production Spars, Deep Draught Semi Submersibles and so on. The deepest well in the world is 10,011ft of water,and the deepest producing well is in about 8000ft of water which is awe inspiring. The industry recognised the difficulty of deep & ultra deep well control and the particular hazards of drilling in deep and ultradeep water, but focuused on preventing a blowout- no-one in the main deep water areas, in the GoM, offshore Brazil, at any stage seems to have said, "But what if it does happen, What do we do then? Do we have the gear and the techniques ready?"
Everyone's faith was put in the BOP stack- that would always work....
RE: use gas lift pump on BP Macondo blowout?
Are the hydrates frozen water with gas molecules trapped in the crystal structure?
If so, does the inclusion of gas molecules change the characteristics of the ice greatly?
Are the hydrates hard ice, slushy ice or something completely different.
In a lighter vein, it seems like hydrates may be a great way to separate the gas from the oil. Now we just have to separate the hydrates from the oil.
Possibly in a future design.
Bill
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"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
David
RE: use gas lift pump on BP Macondo blowout?
I believe they are injecting methanol into the flow on the current cap and agree that this might work in a gas lift pump. (If they knew about hydrates when designing Top Hat, why didn't they inject methanol then?) It would probably take a lot of methanol or glycol. This would not be a problem if it could be recycled, but I wonder how they would get the stuff out of the captured flow. Glycol might be easier to extract, but I don't know whether recycling of either chemical at the site is feasible. I suppose they could take the oil ashore and extract the methanol or glycol and send it back out.
It seems to me that heating might be the best method to prevent hydrate formation. There is plenty of heat available in the flared gas, but it would take some work to get it down to the location of the leak. I would try a controlled fire in the flow first. It would be easier to send oxygen down to the leak than it would be to send heated water down. We know the stoichiometry, and how much gas and oil would have to burn to raise the temperature of the flow by about 40 Fahrenheit degrees. It wouldn't be much, even if the water was half of the total flow.
Not that I am certain that a fire could be sustained in this situation. I am only suggesting that it might be worth investigating.
An expert over at the Oil Drum, handle rockman, has seen the charts of the pressures and other factors in the final stages of the DW operation. Based on those charts, he cannot believe that they did not take drastic action to prevent the blowout. Other experts are saying the same, and also that BP (shorthand) went cheap on the well, which almost guaranteed a blowout.
waross, it looks like a "clathrate hydrate of natural gas", to use the proper term, is denser than seawater, since it collects on the bottom. I know you didn't ask that question, so I am just making an observation. The website I listed in an earlier post has a lot of information on the physical form of gas hydrates, but nothing that I can find that would answer your questions. I am investigating as time allows.
RE: use gas lift pump on BP Macondo blowout?
There is also an article on Wikipedia "Offshore oil spill prevention" with some interesting background on this technology. There is a link in that article to a design for a new top hat, with a seal around the BOP flange, methanol injection, and hot water flowing around the riser pipe. It may be deleted soon, however. See the discussion page.
RE: use gas lift pump on BP Macondo blowout?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.liv
RE: use gas lift pump on BP Macondo blowout?
So far as I can tell, since Top Hat they have been doing everything they can to keep seawater out of the flow. I believe they are not collecting as much oil as they could with the current hat, so that the oil leaking into the sea keeps the seawater out, and they are also injecting methanol. Of course, they don't have enough capacity to lighter all of the oil they are collecting, so that probably has something to do with the amount they are allowing to leak.
An AP news article today says that they have permission to burn oil at the surface now. Therefore they can capture more of the oil than they have been, burning what they can't lighter and keeping it out of the water column, which has got to be an improvement.
docellen, thanks for the Wikipedia reference. After searching around in the references there, I found a report of research conducted by MIT on the Operation Sombrero gas lift pump, which was used on the Ixtoc blowout in 1979 (see my post above on this device):
http://www.mms.gov/tarprojects/032.htm
From the report:
"Test results indicate collection efficiencies of over 90% using the double collector positioned twenty feet above the wellhead."
The report mentions further research:
http://www.mms.gov/tarprojects/085.htm
From that link:
"As oil and gas activities move into deeper and more distant waters, the use of conventional spilled-oil recovery equipment requires further analysis. The prospects are attractive for using large, self-contained collection ships which can deploy subsea collectors over blowing wellheads while remaining on station in heavy weather, recovering oil, and separating out water. An engineering concept and cost analysis of such a system was performed."
RE: use gas lift pump on BP Macondo blowout?
"There is a link in that article to a design for a new top hat, with a seal around the BOP flange, methanol injection, and hot water flowing around the riser pipe. It may be deleted soon, however. See the discussion page."
I couldn't find this information, can you provide the link? Also wonder why the article might be deleted.
RE: use gas lift pump on BP Macondo blowout?
There might be some water in the well fluids, if they drilled to below the oil/ water contact.... without well logs I can't say, but often the first well targets the sweet spot and the second well looks for the oil water contact.
The main issue with using heat to avoid hydrates is that 5000ft is along way down for a surface heat tracing sytem, and burning the well fluids subsea would need a lot of oxygen or air supplied down there, it would be far from controllable and heaven knows what effects it could have.... what would happen to CO2 at this depth and pressure? The lowest risk approach to stop hydrates would be to inject hydrate inhibitors, which is done in producing gas wells and pipelines already, and so is understood and controlable.
Finally, the ship on location now (the Deepwater Discovery, I think) is a drill ship, with limited tank capacity- usually when it does a well test the fluids from the well are just burnt (it's great fun, and a little scary, doing a welltest off a mobile drilling rig; the noise and the heat from the burners as you burn 8000bopd is incredible). According to the BBC BP are hoping to get an FPSO (basically an oil tanker with production facilities on the deck) on location..... isn't it lucky that the MMS has just approved the first FPSO for the GoM so it's not going to be too hard to get permission for that... with a shuttle tanker from a North Sea FPSO to ferry the oil to shore. I wonder if the Jones Act will be waived if necessary for the FPSO or the shuttle tanker, or will that cause more delays???
RE: use gas lift pump on BP Macondo blowout?
Good point about getting the heat down to where the hydrates are a risk. A long time ago, I was in a flow assurance class with a bunch of the Engineers who did the early flow assurance work on Crazy (later "Thunder") Horse in the GoM and they talked about the energy requirements that they were working under. People don't realize how big a heat sink the ocean is. One of the things they were looking at was jacketed pipe with superheated high pressure steam in the jacket. This looked promising until the simulation got near the bottom and all the steam condensed and the pipe collapsed in on itself. I never did hear what they ended up doing. Getting enough heat down that deep is a VERY difficult problem.
David
RE: use gas lift pump on BP Macondo blowout?
However, I am dubious that you have found the right explanation here. If there are shallow water designs for a gas lift pump collector in addition to the Sombrero, which I doubt - see my comments under handle windward at http://www.theoildrum.com/node/6609#more - do you suppose they would have used a riser as small as 1"? At the Ixtoc blowout, 150 foot depth, the Sombrero collector cone was almost 40 feet in diameter at the widest point. I don't know the riser diameter yet, but from pictures of the device it must be at least 1 foot.
I am also skeptical of the objections to heating the flow to prevent hydrate formation. Consider the proposal to heat the flow by injecting oxygen to maintain a controlled fire. How much oxygen would it take? For an order of magnitude calculation, suppose that the oil and gas is leaking at 100,000 bpd, to use the highest estimate I have seen yet. Suppose that an additional 100,000 barrels of seawater are entrained in the flow. Assume that the specific heat of this mixture is 1 btu/lbm/F. To raise the temperature by 40 fahrenheit degrees - as explained in the Oil Drum post noted above - we must supply heat at the rate of 117,000,000 btu/hr. This would require the combustion of about three tons per hour of the hydrocarbons. That would require about twelve tons of oxygen per hour. This seems to be lot, if the consequences of this blowout are ignored. When they are considered, twelve tons an hour is nothing.
If you have evidence that such a fire could not be lit, sustained and controlled, please provide it. As I said in my Oil Drum post, we haven't done the research, even after the warning thirty years ago at Ixtoc that we must have some way to capture the oil and gas from a blowout
When zdas04 writes "people don't know how big a heat sink the ocean is", he is making the same error he accused me of making in an earlier post. How does he know I don't realize it? While I believe that oxygen injection for a controlled fire is the best method to investigate, I don't believe that we can rule out heating seawater at the surface and sending it down. The claim that the pipe would collapse from steam condensation is just wrong. It seems to result from an incomplete analysis of the situation.
Regarding the Jones Act, I believe that it has been overruled to allow foreign ships to operate at the blowout. There are those who would repeal the Act. They are the same people who brought on the DW disaster, global heating, the current and previous financial disasters, the criminal wars in Iraq and Afghanistan (I am a veteran of the Vietnam war. I can see these current wars for what they are. What did we learn in Vietnam? Say no to bullshit. But not enough of us have learned it.), the corruption of the US Department of Justice and many other outrages that have made the collapse of our civilization inevitable.
Also, if there had been no Jones Act, I would not have been able to get a job on the Bridgeton (ULCC) in 1989 when I sorely needed that job, although that job opened up because of the first Gulf War, which would not have happened if there had been rational and responsible people in office these past thirty years. Those who would repeal the Jones Act would only save some money for those who don't need it. Why don't we outsource their jobs to China? It would certainly improve matters the world over.
RE: use gas lift pump on BP Macondo blowout?
Sorry, but that quote is complete rubbish and makes me highly suspect of the rest of the content.
"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.liv
RE: use gas lift pump on BP Macondo blowout?
When I said "People" don't realize how big a heat sink the ocean is, I meant "people" in the generic sense--as in it is difficult to accept how big the heat sink is.
I didn't work on the project I referenced, one of the Engineers who did work on it related the results of their thermodynamic model over a beer after class. He was a pretty sharp guy with no reason to lie to me. He also had the material specs on the jacketed pipe that they were considering, I don't. My guess is that his analysis was faithfully performed and the results that he reported included a competent review of that data. I'm sure that you know more than he did so I'll withdraw from the discussion.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
"It is always a poor idea to ask your Bridge Club for medical advice or a collection of geek engineers for legal advice"
RE: use gas lift pump on BP Macondo blowout?
If you would analyze the system, you would see that I am correct. I did prepare an explanation, but it is long and boring and I will not inflict it here. If you want to prepare a long and boring explanation, I will read it to see where you went wrong.
David, I am hoping Big Inch comes through. After all these years, you will have a definitive answer to that classroom problem.
RE: use gas lift pump on BP Macondo blowout?
http://www.energy.gov/open/oilspilldata.htm
There are two links at the bottom of that page to PDF files on the LMRP system and device. The second one has some interesting drawings.
There are a bunch of other links to good technical info in the old Wikipedia article, which is now preserved in the original authors sandbox. See the top link on the discussion page for the article "Offshore oil spill prevention".
The problem with the original article seems to be less interest in engineering, and a bunch of folks wanting to push the article in a different direction.
RE: use gas lift pump on BP Macondo blowout?
On another topic, has anyone seen or heard of a well with multiple wellheads? That would allow them to relieve the pressure on the main wellhead while fixing the BOP. All it would take is some extra piping, not extra drilling. Too late for the current disaster, but it might help the next time a BOP fails.
RE: use gas lift pump on BP Macondo blowout?
"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.liv
RE: use gas lift pump on BP Macondo blowout?
12 tonnes/ hr of O2? What's that is terms of volume? Well, 1 mole of O2 is 16g so 12 tonnes is 750,000mole, molar volume of an ideal gas is 24.46litres (Google is your friend!) so so that's 18,345,000litres / hr (18,345m3/hr or about 250,000scf/ hr of oxygen that needs to be compressed to about 2,200psi .... I'm sure there's a pipeliner on this boards that can help me out, but those look like quite large numbers, and I'm guessing you don't get a compressor capable of 20,000m3/ hr rated at 150bar in less than 6 months lead time!!!!
RE: use gas lift pump on BP Macondo blowout?
Also, you either need an air plant to extract 500 MCF/hr of oxygen from air or you need to inject air. The lead time on an air plant is years, so plan on injecting air. Multiply the doubled value by 5.
Now you either have to have REALLY big pipe or accept that friction is going to eat a lot of your pressure at that sort of flow rate and assume that the surface pressure is 3500 psi. That requires a 4 stage recip compressor (or more likely a 6 stage centrifugal or axial) and around 600 hp/MMCF.
So to move 60 MMSCF/day of air to the sea floor would require something like 36,000 hp. Not a small compressor station. The air permit alone would require 2 years under normal circumstances. Which isn't a problem because compression hp that specialized and that big would take 2-4 years to acquire anyway.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
"It is always a poor idea to ask your Bridge Club for medical advice or a collection of geek engineers for legal advice"
RE: use gas lift pump on BP Macondo blowout?
Suppose we start with liquid oxygen. Many plants already in existence could supply twelve tons per day, and a tank could carry that much on a service vessel.
At the leak site, use the heat from the flare to expand the LOX into the injection pipe. This would eliminate the compressor, but it would require a pump for the LOX to generate the injection pressure. Is there such a pump? It would be like the feed pump in a Rankine plant.
Suppose it would be better to use a compressor after the LOX has been vaporized. In this emergency, perhaps one could be found right away. In my time with Rolls Royce, we sold a lot of RB211 compressor units of at least 36000hp, but I was in the engine division and don't have much knowledge of compressor capacities. David, some of these units were for sending raw gas ashore for processing. They were high pressure drum types. The centrifugals for pipeline service would have too low a pressure ratio for this job. Would a drum type produce the pressure and flow?
This is all supposing. Probably none of us have the time, much less the resources, to determine whether this idea would work. I appreciate your input and hope you will stay with it for awhile. If the idea is worth a try, it would take some equipment, but look at what they are deploying now to capture only some of the oil, and the situation looks like it could get a lot worse. What do we do then?
docellen, thanks for the links, I will be looking at them.
Big Inch, I like the graphic. Can we overlook the recent unpleasantness and have your expert opinions here?
RE: use gas lift pump on BP Macondo blowout?
Windward. The great problem with solving the problem is finding out what the problem is. I believed that it may be possible to completely close the BOP. It possibly is, but bp didn't tell anyone in a timely fashion that they suspected a bad casing. Knowing that, it may be safer for sub sea bed conditions to increase the flow of the BOP. Given the latest postings, it may be too late.
Re the gas lift. I have trouble understanding the need for a gass lift. There is ample pressure in the well to move the oil to the surface.
In a shallow leak, and low pressure oil, a gas lift may raise the oil from the sea level to the deck of a collection ship.
Hydrates are a problem when water is present.
We don't know if there is water in the oil or not. Given that the production from the latest kludge seems stable, I doubt that there is much included water.
Here, as information comes out in little bits and drabs, the limiting problems now seem to be:
1> The casing is compromized below the sea bed. More flow through the BOP is better than less flow.
2> bp believed their own estimates and do not have enough surface facility to handle any more oil than they are presently collecting.
3> I can't see wasting time and equipment to bring any more oil to the surface when they don't have a pot to hiss in. Well, it may be better floating on the surface than drifting in a cloud below the surface, but you get my point.
When they get enough surface capacity to handle the flow, I am sure that they will be able to collect almost 100% of the oil that is leaking from the BOP. If they are able to increase the flow so as to reduce presure on the compromised casing they will probably do that as well.
Now if they reclaim the concrete mausoleum and fill in the side holes to prevent the ingress of sea water and open the top a little, they may be able to drop it over one of the seaps to collect that oil. A gas lift may be useful there. Adding a LOX burner to clear any hydrate buildup may be useful. I surmise that clearing any hydrates resulting from entrained water will be much less burden than clearing hydrate buildups resulting from the ingress of sea water.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
I know this thread is long and previous posts forgotten. I proposed this gas lift idea for catching the oil after it is in the water. If they can cap the BOP and direct the oil to the surface, the pressure in the reservoir will provide the driving force as you say, aided by the gas lift that also occurs in that case. The gas lift I am proposing would be for the oil and gas that escapes into the water, where the well pressure is useless.
There is probably very little if any produced water, from what I have read. The oil that is still leaking into the water does prevent any seawater from entering the flow up the riser, which would probably clog with hydrates otherwise.
If BP does not have enough lightering capacity yet, shame on them, but now they have permission to burn the oil that comes up. It seems to me that the best way to get all of the oil up, especially when there is no hardware below to latch on to, is to install a gas lift pump. Got to deal with the hydrate problem in that case. The controlled fire is the best thing I can think of, and I do not know if it would work. It seems possible, since it works with oxy-acetylene torches under water. Thanks for a good post.
RE: use gas lift pump on BP Macondo blowout?
ooops... well I just make holes in the ground... I'm not a process engineer!
Windward- I know about RB211 compressors (the last offshore platform I was on had three of them for gas lift and two enormous John Brown frame 7s for the gas export line to shore)... but you don't get them off the shelf do you?
It would be very hard to put multiple wellheads on a single well- the wellhead has to hold and seal the casing and there's only one set of casing strings per well...
One of the questions about this blowout is the failure of the BOP system. The Deepwater Horizon's BOP had two annular preventers, three pipe rams with variable bore rams, a casing ram with 7" rams a blind/ test ram and a Shear/ blind ram. None seemed to close (or close fully) when the ESD switch was actuated from the bridge. Neither did the LMRP disconnect from the top of the BOP when the ESD switch was hit (imagine if at least the LMRP had worked- a lot of oil spilling into the sea until another rig arrives, run a new riser & LMRP onto the BOP, engage, and breath a sigh of relief.....) and then the automatic deadman switch, that should work if the BOP looses electrical, command and hydraulic communications with topsides should close the shears and the annuluars. That doesn't seem to have worked either.
So why not?
RE: use gas lift pump on BP Macondo blowout?
On the multiple wellhead point, I believe waross was referring to the speculation, and some evidence, that oil and gas have started to come up through the seafloor at some locations away from the BOP, because of damage to the overlying layers of the reservoir or failure of the DW casing below the seafloor.
I think that if BP needed a compressor, usual lead time one year, they could get one in a few days from some rig somewhere in the world. BP certainly has a few. Their competitors should also be interested in stopping this blowout. One of them would probably provide a compressor in this emergency. If they have to shut down production to do it, they would be well paid for it.
Can you give us some details about the RB211 gaslift operation? What was the pressure and mass flow of the gas, what other equipment was needed, just a general explanation of the operation would be very interesting.
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
Let me try again. I'm thinking of something like a TEE that is used in common plumbing, but of course, much bigger. Run a pipe off to the side, add a 90 degree elbow facing upwards, another short section of pipe, and a cap that can be quickly removed to install an emergency riser. Everything but the cap should be underground, to minimize the possibility of sabotage.
I share your astonishment that everything seems to have failed in the BOP, although it is not surprising that the shear rams failed. As I understand it, they are not rated for deepwater pressures.
Question: Why don't they have some kind of quick connection so they can apply external hydraulic pressure, and close the rams when all the high-tech stuff fails?
RE: use gas lift pump on BP Macondo blowout?
If the disconnect has worked, the initial spill rates would have been terrible, but the action would have been: Discoverer Enterprise runs it's BOP and Riser over the existing BOP, latches on, energises the seal, and then either flows oil to surface up the riser or closes the new BOP. Drill the relief well to kill Macondo, and everyone goes home.
A Tee as you suggest wouldm't really work, as the flow would take the path of least resistance and continue up the broken pipe.
The issue about the shear rams isn't the water depth, but that shear rams anywhere, onshore, shallow water, deep water, are designed to cut the drill pipe tube, and not the extra thick walled bits of drill pipe at each end- the tool joints. On a 30ft piece of drill pipe, tool joints are 12- 18" long at each end- so 7- 10% of the drill pipe can't be cut with the shear rams.
I think this may change very soon...
RE: use gas lift pump on BP Macondo blowout?
A question concerning rupture disks. I have seen and worked with several types of small rupture disks used for various reasons in surface applications.
There has been speculation that a rupture disk may have failed 1000 ft. below the sea floor. Can you explain to us the arrangement and purpose of this disk?
Thanks
Bill
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
So I'm guessing what happened is that nobody had time to hit the Big Red Button when the fit hit the shan, and their backup plan was trashed in a pile of twisted metal. What I'm thinking of is something that will work even in that circumstance. No doubt you can think of even better ideas, but here are my suggestions:
1) Separate quick-connect nipples on the side of the BOP that go directly to every actuator in the system.
2) Clamps instead of bolts on all flanges. These should be easily operable by ROVs. The clamps should also have a well-calibrated breaking strength, so we never have to worry about extreme forces breaking something not designed to break.
3) Multiple wellheads. I'm still not convinced that this won't work. With an extra outlet to relieve the pressure, it won't take much to hold off whatever is coming straight up. You might even put the normal riser on the side connection, allowing emergency access straight down the center pipe.
If they had all this in the current situation, the action would have been: Pop the BOP, grab the drill pipe, and blow some mud as far down as it will reach. If that just blows mud in your face, pull the broken drill pipe and insert a pipe with some kind of plugs that grab the inside of the well casing, maybe one every 500 feet through the zone where the gas and oil is flowing in.
Question: How much force, worst-case does the casing and cement have to hold back? I've heard the pressure at the wellhead could be as high as 15,000 psi. On a 36" diameter wellhead, that could produce enough lift to make those steel pipes stretch like taffy, ripping loose from the cement in a thin zone moving quickly down the entire length of the pipe.
RE: use gas lift pump on BP Macondo blowout?
"We have a leadership style that is too directive and doesn't listen sufficiently well. The top of the organisation doesn't listen sufficiently to what the bottom is saying." Tony Hayward CEO BP
http://www.youtube.com/watch?v=hpiIWMWWVco
"Being GREEN isn't easy." Kermit
http://virtualpipeline.spaces.liv
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
They might be in the 16" casing string, but I cannot think of any reason on earth why you would do that in casing....
RE: use gas lift pump on BP Macondo blowout?
"It seems to me that heating might be the best method to prevent hydrate formation. There is plenty of heat available in the flared gas, but it would take some work to get it down to the location of the leak. I would try a controlled fire in the flow first. It would be easier to send oxygen down to the leak than it would be to send heated water down. We know the stoichiometry, and how much gas and oil would have to burn to raise the temperature of the flow by about 40 Fahrenheit degrees. It wouldn't be much, even if the water was half of the total flow."
Why not go the whole hog, and burn ALL the disgusting stuff at the point(s) of emanation:
http://tinyurl.com/3yeqald (or for more "confidence": tinyurl preview facility: http://preview.tinyurl.com/3yeqald)
For further genesis/background/development/further info on idea:
http://tinyurl.com/3ae4jj3 (or via: http://preview.tinyurl.com/3ae4jj3)
To MY surprise, I've been pretty much right about most likely pitfalls, stuff that BP appeared to me shouldn't really be doing: like when they tried their "Top-Kill". Immediately I saw their first large dome collection effort, I was quizzical as to why sluice gates of some sort didn't seem to be evident on pictures I saw of it - so pretty clearly the thermodynamic conditions would be changed drastically; as it turned out, leading to clathrate formation. This prompted me to generate the following "1st Submission", which also carries a warning against "Top Kill/Junk Shot" in a fairly stark fashion:
http://tinyurl.com/37oeenj ("Sluiced" Dome)
As far as the stoichiometry is concerned, does anyone here have a handle on what the "average fraction" of the gunk is? (I guess I mean roughly the average value of "n" in C(n)H(n+2), ignoring Benzene & stuff!). 'Course the flow rate is a problem, I guess Prof. Wereley's (Purdue Uni.) approx. 25 gals/sec. would be a good first assumption.
I think one of the problems with undersea incineration is not getting it to burn, or keeping it lit (as long as oxidiser is supplied), but owing to the very high pressures, and so the much closer association of molecules, that the burn would be extremely hot - not too good for supply pipe longevity and such.
As far as getting hold of the humungus compressor or compressors required, I realise that the Corporatocracy doesn't permit much Govt power these days, but I think there's a good case in this emergency to darn-well REQUISITION whatever is available NOW, even to the extent of ripping apart existing non-critical installation(s).
See also a thread I started on this at a well-known Brit. newspaper's talk board (which is how I found eng-tips ( ...
ht
It's a Brit. talkboard, so the ... er ... language can get a bit ... er ... loose there ... including mine - I'm Brit. too.
All the Best,
Dennis Revell
RE: use gas lift pump on BP Macondo blowout?
Sorry screwed up one of the PDF file-links (have so many versions on my PC, I'm losing track
[BEGIN CORRECTION:]
"For further genesis/background/development/further info on idea:
http://tinyurl.com/2coku5f (or via: http://preview.tinyurl.com/2coku5f)"
[:END CORRECTION]
Thanks,
Dennis Revell.
RE: use gas lift pump on BP Macondo blowout?
Regarding the possibility of starting a fire in the flow at the 5000 foot depth, I haven't had time yet to review Le Chatelier's principle and the chemistry of it. Maybe it wouldn't work because of the high pressure, but if it would, I believe the fire could be managed to prevent any damage to the piping.
If we can't collect all of the oil, either at first or after many attempts to do so, I agree that it would be better to burn it rather than allowing it to enter the water. However, burning it at the 5000 foot depth would require an enormous flow of oxygen, far greater than what would be required for the fire I am suggesting.
On the Oil Drum, I proposed that they burn all of it at the surface, if that could be done safely. This would require a tight seal on the BOP. I believe that is what they are approaching now, very cautiously, because of uncertainty about the condition of the casing below the mudline. There is much more to say about these things, too much to go into in one post.
In the beginning there was about 40% by mass of natural gas in the blowout. That has declined a little since then, but even now the fraction is far above the average for an oil find.
On the clathrate problem, I now have a copy of the book by E.D. Sloan that whammet listed above. I will comment later on what I find there.
I also agree, if they need any equipment, requisition it now and settle later.
If you have been right about this thing all along, and I have no reason to doubt that since I haven't studied your proposals yet, then that is probably why you are not in a position to do much about it. Corporate culture and government agencies - should I say the human race? - do not like those who don't conform to groupthink.
Sometimes this makes sense, for example when sea monsters and 100,000 psi gas bubbles and sinking a million ton nuclear battleship (must build one first) on the blowout are being discussed by some in this case. But so far, I haven't seen any good ideas from those in charge either. In particular, why weren't we prepared for a blowout like this? That was assured on paper but never in practice. This is what we get from the free market ideologues who have been running things for a long time now, who believe self-regulation always works and corporations always act responsibly.
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
In a blowout under water, we must have some way of capturing the oil and gas AFTER it is in the water. If there were always a BOP or some piping left after the accident, and if we could always put a tight seal on it, and if we could always accomplish the job quickly, then relatively little oil and gas would get into the water at the blowout depth. (What to do with it after it has been brought to the surface is another matter.) Also, because of the tight seal, there would be no chance of hydrates forming and stopping the flow. If we can always meet all of these requirements, then there would be no need for a device such as a gas lift pump. And there would be no need to consider how to make it work, which in some cases would require heating the water.
So far, they have been afraid to use a tight seal on the Macondo BOP. It would increase the pressure on the casing below the mud line, and they discovered during Top Kill that the casing might be damaged. Increasing the pressure on it might make the blowout worse - oil and gas blowing up outside of the casing through the sea floor, therefore less of it collected with the hat.
They have been slowly closing down on the seal, reducing the amount of oil and gas that leaks and sending more of it up the riser. They also plan to install another riser. Going slowly, they can determine whether they have reached a point where they must stop tightening the seal, to avoid further damage to the casing.
Maybe they will eventually get a tight seal and capture the entire flow. In the meantime, millions of barrels of oil have leaked into the water. The only good part about this is that the leak keeps water from entering the flow, so they don't have to worry about hydrates plugging the riser.
I believe that a gas lift pump could have been capturing all of the oil and gas at Macondo almost from the beginning, if they had been ready with it. The oil and gas is ALREADY entering the water, and it is taking a very long time to stop even a fraction of it. This requires some means of capturing the oil and gas AFTER it is in the water, and a gas lift pump is the best solution, in my humble opinion.
For a gas lift pump to work, one of the problems we must solve for a blowout like Macondo is that the water is nearly freezing and the pressure is very high. These conditions ensure that hydrates will form rapidly. Since we can't reduce the pressure, we must heat the water - actually the water/oil/gas mixture - enough to prevent hydrates, because a gas lift pump also has a riser, and hydrates would plug it up.
However, not all blowouts would require heating of the flow to make a gas lift work. It depends on the pressure and temperature at the blowout.
As long as we drill underwater, we will need some device of this kind. There will be blowouts that cannot be controlled with the BOP, for example Ixtoc. That is, there will always be blowouts that cause oil and gas to enter the water at the depth of the blowout, and it will be too late for any tight seals, and impossible to install them anyway. When Ixtoc blew, twelve thousand feet of drill pipe and other equipment fell onto the BOP from the rig above. It was difficult for divers to reach the BOP, and when they did manage to close it, it soon failed and they were back to a blowout.
After nine months and two relief wells, the well was finally killed. In the meantime, because the blowout was so large and all of it was entering the water, they tried Operation Sombrero - a gas lift pump. But this idea had never been tried before, and they did not have a proven design or a way to install it. They had to work all of that out first, which took several weeks.
After they installed it, the Sombrero worked to some extent, not perfect, and it captured about 10% of the oil and gas in the entire blowout. But after two months of operation it was damaged by heavy seas and removed.
They didn't need to heat the water at Ixtoc, which was in the southern GOM. The water was already warm - not near freezing as it is at Macondo - and heating was not required because the blowout was only 150' deep, so the pressure was far below what would have caused hydrate formation at that temperature.
You can read about the Ixtoc blowout and Operation Sombrero in the book "Offshore Pioneers: Brown and Root and the History of Offshore Oil and Gas (authors Pratt, Priest and Castaneda, 1997). There are other references on the Oil Drum, just search for Ixtoc.
If research had continued on the Sombrero, we could have used it at Macondo. But the oil companies didn't want to spend the money (!), and the government did not force them to develop it because the regulatory agency MMS was a wholly owned subsidiary of the oil companies. We will see if renaming the agency does any good. Whoever dreamed up the new name ought to retire. The acronym alone is a mouthful, BOEMRE, pronounced "bummer". Maybe the bureaucrat has a dark sense of humor.
The Associated Press published a good article yesterday, "Little Spent on Oil Spill Cleanup Technology":
http://
From the article:
"'Why they didn't start working on it after the (Ixtoc 1) Mexican spill [sic] in 1979 is beyond me,' said Gerald Graham, president of World Ocean Consulting, an oil spill prevention and response planning firm in British Columbia. "Now they're trying to catch up.'"
I wonder what Dr. Graham himself was doing about it before Macondo. Did he just get into the business?
RE: use gas lift pump on BP Macondo blowout?
A very important step in problem solving is to define the problem. Another important step is to identify and quantify the factors that may be affecting the problem.
Trying to solve this problem based on the information that bp is releasing is an excercise in futility.
Why can't bp collect more oil? In case you missed it, they based their plans on a quantity of 5000 BPD, even though they were told that they were probably leaking much more. Hubris prevailed. They are now playing catch-up and trying to get more facilities on site.
To answer the question;
"Why don't they just close the vents?"
Not safe. They are collecting and flaring all the oil and gas that safety will allow. When they get more ships on site and are able to collect and/or flare more, they may indeed close the vents. As for hydrates, there may be water in the oil/gas stream.
They may be heating to separate the gas at a lower level for some reason.
Who knows?
Let's hope the relief well goes well!!
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
As for the danger to the well casing in closing the cap vents, that doesn't make sense to me. The pressure in the cap is only a few hundred psi at the most. The pressure in the well casing is thousands, if I understand it right. They already added a few thousand more in the top-kill attempt, and the casing survived. So I think adding a few more tens of psi by closing the vents won't make much difference down in the well.
Waross, I like your Peter Principle theory. I can easily imagine the top brass at a company like BP not listening to their engineers. I can also imagine that the Coast Guard doesn't listen to engineers either. What I'm having a hard time imagining is how Steven Chu might have gotten roped into some misleading story. If anyone can punch through the organizational politics, and ask the right questions, it would be him.
I also understand your caution that we can't solve the problem with only the information BP is releasing. Still, I am finding this a fascinating mystery. There are plenty of clues, including what Dr. Chu has published on the DOE website http://energy.gov/open/oilspilldata.htm.
RE: use gas lift pump on BP Macondo blowout?
Why? It looks as if bp believed their own Bullshot that there was only 5000 BPD leaking and planned accordingly.
Usually an engineering disaster is blamed on one of the victims. In this case, the downward pressure on the share prices and the dividends may result in the share holders meting out to the directors and senior executives a just reward for the "Profit at any expense" culture that they have allowed to develop.
My sympathies are with the victims, both immediate and long term and with the thousands of good people in the bp organization who may suffer from the effects of this disaster. No sympathy for the supervisors, managers and executives who developed this culture, and not much for the shareholders who have benefitted from the extra profits generated by the risk taking over the years. I hope that pension fund managers are taking note and considering how companies achieve the bottom line instead of looking at the bottom line to the exclusion of other factors.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
Shareholders should pay the cost of this disaster, not because we deserve to be punished, but because it is the right thing to do. As for punishment of those responsible, I think BP shareholders will see to that. The other oil companies should consider themselves lucky. I believe the problems we are seeing are industry-wide.
RE: use gas lift pump on BP Macondo blowout?
A few years later I was on another short term contract with the same contractor. The same procedures were still in effect. Kept my mouth shut and kept my job. A few days after a legitimate layoff, there was an incident due to the "short cut" procedures. Fortunately no injuries, but sending men to work on an energized transformer with a flawed lock-out plan is not a nice thing to do. The owners safety department removed the contractor from site immediately, but allowed the workers to transfer to the replacement contractor. It was nice to see.
You understand my predudice.
And I didn't say no sympathy, just not much.
Remember, bp bet the lives of 11 men against your return and lost. A little pressure from pensioners on pension plan managers to do a little more due diligence may be in order.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
And so to my reply to some of yours:
"Dennis, your comments are interesting and I will read the information at your links."
Thank you.
"Regarding the possibility of starting a fire in the flow at the 5000 foot depth, I haven't had time yet to review Le Chatelier's principle and the chemistry of it. Maybe it wouldn't work because of the high pressure, but if it would, I believe the fire could be managed to prevent any damage to the piping."
I think you'd need more than Le Chatelier's Principle, which is, pardon me, kind of "airy-fairy" and hand waving. You'd need to get deeper into Gibbsian Thermodynamics: Chemical Potentials, Law of Mass Action-Equilibrium Constants, Degrees of Reaction, Chemical Affinities, van't Hoff Isobar (for combustion temperature calculations), and the like. The calculations can, in principle, be done, but would be horrendous - a different one for each fraction in the gunk, then the whole lot "summed" together, or as one huge most likely intractable heterogeneous system (which is what we have here). I had occasion to (re-?)read, and understand - though a lot of the stuff is ... er .. tricky - an old copy of Zemansky's "Heat & Thermodynamics" from soup-to-nuts, beginning a couple or so years ago. I have the 5th edition, and in that the relevant chapters are Chapters 16 ("Chemical Equilibrium") to the end of the book (Chapter 18: "Heterogeneous Systems") - few in number but all "heavy" chapters. In addition a reader pretty much has to understand most of the stuff in the preceding chapters to follow the relevant materials in those last chapters!
My copy is probably unreadable by anyone else now - as virtually every page is covered in my pencilled scribblings - but they're legible to me, and so though I'm now rusty on it (as you get on pretty much anything not used every day), a quick glance prompted by your post makes enough it come back comprehensibly. And indeed the calculations would be horrible. Hence in light of a) not having information on the gunk fraction makeup b) only guestimates as to the gunk flow rate c) It being extremely likely that combustion reactions of the various gunk fractions have not been characterised under the P-T conditions at the sea floor - so you'd be guessing, for example, at a value for the Ks - the Equilibrium Constants, or at best making very rough calculations/extrapolations, I decided not to bother! Hell, even assuming if I could do it, I haven't the time to do everything myself
So I looked for a contemporary comparison: No doubt there are others, but I figured the Space Shuttle main engine combustor chamber has no problem whatever maintaining a very intense burn at a pressure of 3,000 psi. Of course, there are important differences: we're talking H2 & O2, with undoubtedly very well known thermodynamic characteristics, and a Degree of Reaction almost infinitesimally close to unity under virtually all imaginable conditions. In addition, the external pressure is 14.5 psi and not ~2,000 psi. So, this is my handwaving part: it's difficult to imagine that the Shuttle main engine would not burn its fuel well even fighting against a much higher external pressure of ~2,000 psi. Oil fractions are also normally extremely flammable - even the more exotic ones, as a quick read of the "high flammability" warnings on the more exotic HC derivatives in my garage reveals. I therefore think it more than reasonable to conjecture that the Degrees of Reaction for most of these fractions will also be close enough to unity under the conditions pertaining at the sea floor - assuming an appropriately sized incinerator chamber of appropriate geometry, of course.
In fact, I feel so strongly that this is the case, though, as said proviso'd as still being hand-waving, that currently I see more reason to be more concerned with the burn temperature being just too high. That's why the PDFs I've prepared pretty much all now insist on a refractory lining for the incineration chamber; so I'm more concerned with the "knock on" heating effect on oxidiser feed pipe(s), and now that they've cut off the broken riser (darn) the effect on what's left of the LMRP/BOP. A complication, but it may be best to provide some heat insulation mechanism between those and the incineration chamber. That's why I "lifted" Fig. 2 into the latest PDF update - that, or a variation on it does seem to give more opportunity for heat/combustion chamber insulation from the LMRP/BOP.
"If we can't collect all of the oil, either at first or after many attempts to do so, I agree that it would be better to burn it rather than allowing it to enter the water. However, burning it at the 5000 foot depth would require an enormous flow of oxygen, far greater than what would be required for the fire I am suggesting."
Yes, it would be an enormous flow. My concerns here are 1) I'm not happy about using pure O2 for likely combustion temperature reasons given above - perhaps some "happy compromise" mix between pure O2 and air - to prevent associated steel items from burning up themselves? Also I've wondered if it may be possible to feed some non-gaseous chemical high oxidiser down with the air/O2, to reduce the prodigious volume requirements for the latter? 2) The shock of the oxidiser gas flow would have to be considered - this is why I show two "balancing" oxidiser inputs in the first figure in the PDF. In addition the law of the conservation of angular momentum may be put to good use here: If the inputs are angled (looking down against the plane of the sea bed) more than shown in that figure, a vortex flow would be established. In addition to these being known to be extremely stable, lateral shock/forces on the incinerator system would be minimised (in theory would be zero).
"On the Oil Drum, I proposed that they burn all of it at the surface, if that could be done safely. This would require a tight seal on the BOP. I believe that is what they are approaching now, very cautiously, because of uncertainty about the condition of the casing below the mudline. There is much more to say about these things, too much to go into in one post."
That would be ideal. I'm forced to believe, however, given the "progress" on this catastrophe, that either i) A tight seal is impossible to achieve or ii) BP/others are now pretty well convinced it would wreck the stuff below the sea bed - which they most likely caused some damage to themselves in their, IMO, inadvisable "Top Kill" attempt.
...
"On the clathrate problem, I now have a copy of the book by E.D. Sloan that whammet listed above. I will comment later on what I find there."
Well, I can only imagine that the only thing of use would be accurate Clathrate Phase/Eutectic diagrams. Those would pretty much be the "deciders". I did some more arm-waving here, more intuitive than not, I hope: Obviously (and sadly!) blocking Clathrate build up does not occur with unrestricted flow - so the "trick" is that whatever collection method is had better not make the Thermodynamic State drift too close to an undesirable place on those phase diagrams: so (without external heating) the flow rate (and so the back pressure) can not be too much interfered with. Catch 22 somewhat.
"I also agree, if they need any equipment, requisition it now and settle later."
But according to some, even not counting the Supreme Court, that would be interfering with the "God" given rights of Corporations as living breathing individual souls ...
"If you have been right about this thing all along, ... "
That may have been a slightly overenthusiastic claim on my part
"and I have no reason to doubt that since I haven't studied your proposals yet, then that is probably why you are not in a position to do much about it. Corporate culture and government agencies - should I say the human race? - do not like those who don't conform to groupthink."
That's how it feels to me! Even Bill Nye the "Science" Guy, or at least those in his orifice, must figure he's some kind of rock star, prima-donna or something ... not to be bothered by we "hoy-polloy". I E-Mailed him, and called his office - from the number given on his resume at his website - to confirm receipt and the hope that the E-Mail would be brought to his attention ('cos I realised he must get a lot - esp. after his TV appearances on the GOD). All the lady I spoke to could talk about was insisting that I tell her how I got "this number". She was all but calling me a liar even when I insisted it was on his website! I managed to avoid using expletives on that occasion, but I probably will not in any future similar situation.
"Sometimes this makes sense, for example when sea monsters and 100,000 psi gas bubbles and sinking a million ton nuclear battleship (must build one first) on the blowout are being discussed by some in this case."
Yeah, I realise and appreciate all that. But be assured I have almost literally been banging my head against a brick wall to get some attention paid to this - just one reply, for example from Prof. Chu, or Prof. Michio Kaku, say, to the effect that the combustion temp would reach 4,500 degs C, and no known materials/mechanism that would withstand that can be quickly assembled would have stopped me from pestering all these apparent rock stars (bad example: I'd have just said make a bigger chamber! ...
"But so far, I haven't seen any good ideas from those in charge either. In particular, why weren't we prepared for a blowout like this? That was assured on paper but never in practice. This is what we get from the free market ideologues who have been running things for a long time now, who believe self-regulation always works and corporations always act responsibly."
Yes, the Milton Friedmanites and the Grover Nyquisters will be lauding the "Free" Market right up to the very day it puts an end to us all.
All the Best,
Dennis Revell.
P.S: I've uploaded a file (at least I tried to) that "zengineer" posted at the innocentive website (you have to register there even just to view the threads - so I'm pretty much stopped going there). The upload should be with this post. It's extremely simple, and as I said to him in a reply there, I can't figure why it wouldn't work (well at least before BP compromised the piping/equiptment with their ill-advised "Top Kill" attempt).
RE: use gas lift pump on BP Macondo blowout?
Closing the vents can't add any significant pressure at the wellhead. There must be some other explanation as to why they continue to let the oil flow into the water.
I talked with a retired petroleum engineer who has written articles on methane hydrates, and he suggested there might be a problem with the water already in the oil coming from the reservoir. Unfortunately, he was not an expert in oil drilling, so he couldn't do anything more than speculate. I'm still finding it hard to believe that a small increase in pressure in the cap would cause a huge increase in hydrate formation.
RE: use gas lift pump on BP Macondo blowout?
I was glad to have the combustion information. I thought I would start with Le Chatelier's Principle, to see if that simple method would nix my idea. But if it did not, until I read your post I did not realize how much more work would lie ahead. I defer on this to anyone who has heavily annotated every page of a thermo text. Zemansky's book sounds like a real treatise in the old style.
I have read your pdf "Undersea Flare Dome (UFD) Effective Mitigation for Gulf Oil Leak". I see now why you are concerned about the heat, since your fire would be a lot larger than the one I am proposing. I offer this approximation: the temperature of the inside of the steel wall of your furnace would be very close to the outside temperature, since steel conducts heat pretty well. This is a rule of thumb in heat transfer, rough but useful.
For example, from the 39th Edition of "Steam" (Babcock and Wilcox, 1978): "In evaluating the overall resistance [to heat transfer], the metal resistance may be neglected without serious error." If there is cold seawater on the outside of the furnace, and the seawater is well-circulated over the walls, then the inside metal temperature will not be very much higher than that of the seawater. I am now prepared to be corrected on this by the experts, and possibly others.
I was thinking about the space shuttle main engine also. I believe that the combustion chamber is cooled by the LOX and liquid hydrogen, by directing them through channels or piping surrounding the combustion chamber. This also heats and expands them somewhat, aiding combustion.
Concerning the pumping of liquid oxygen (see earlier posts on this speculation), a pump of sufficient pressure and flow for my proposed small fire must have been developed for the space shuttle. Your large fire would require several pumps.
You have done a lot of work on your idea and it deserves an analysis and reply from BP. The only change I would make to your pdf is to add an abstract, to explain immediately that you are proposing to burn the entire flow right at the blowout. I knew this before I read it, but for those who don't, an abstract would make it clear.
Docellen's point about pressures seems right. Concerning water in the flow, water that comes up with the oil and gas from a reservoir is called produced water. On the Oil Drum awhile back, someone posted a chart and comments to indicate that there is no produced water at Macondo. Hence, there would be no hydrate problem if the flow going up the riser is not contaminated with seawater, however this may be accomplished.
RE: use gas lift pump on BP Macondo blowout?
Alternately, a small combustion at depth to generate some gas lift in the riser and enough heat to nulify hydrate formation. Then the main combustion close to the surface. And if the near surface combustion device is comprised of a primary and secondary burner the velocity of the waste gas and unberned oil exiting the primary burner may be sufficient to use a venturi to supply air to the secondary burner.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
Since a high velocity has already been generated at the surface, it should be possible to separate the flow with a centrifugal separator. Then the oil and water could be captured for further separation, and the gas flared. Would this not be better than burning all of the oil either at depth or higher up?
For an alternative to a small fire at depth, electric heating elements could be assembled as a screen on the bottom end of the riser over the BOP. Seawater flowing over them into the flow up the riser would pick up enough heat to prevent hydrates. The screen could be designed to keep the seawater flow to a minimum. It might be easier to send electric current down to the screen than sending oxygen down for a fire.
DrillerNic, suppose they start to get produced water, although that sounds unlikely from what you have said. I read that the temperature of the blowout is at least 150F at the BOP. If all of the flow was going up a riser that is tightly connected to the BOP - no seawater entering - do you think the temperature would drop fast enough to cause hydrates? The pressure would also be dropping, acting against hydrates. I wish I had time to do some calculations, after a long review of how to do them.
RE: use gas lift pump on BP Macondo blowout?
The issue is when cold seawater mets free gas at high pressure- that's how you get the temeprature, pressure and composition combination to form hydrates.
RE: use gas lift pump on BP Macondo blowout?
RE: use gas lift pump on BP Macondo blowout?
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RE: use gas lift pump on BP Macondo blowout?
At Macondo the pressure is over 2000 psi at the 5000 foot depth. Even though the gas fraction was very high there, over 40% by mass, the volume flow was not large because of the high pressure.
Compare this to Ixtoc, where the water depth at the blowout was 150 feet. Like Macondo, there was a lot of gas, and the total oil flow was about the same. But at Ixtoc, the volume flow was much greater because of the low pressure.
We must also design a collection dome to attach to the bottom of the riser. After the Sombrero was installed at Ixtoc, they found that the dome was much too small. However, that was mainly because PEMEX greatly underestimated the size of the blowout. They said it was 5,000 bpd when it was closer to 40,000.
PEMEX probably knew it was that high, but didn't want to report it even to their gas lift designers, Brown and Root. It appears that BP/USG did the same thing at Macondo. I think they greatly underestimated the flow for public relations. There is evidence that their experts soon knew that the flow was much higher.
At Macondo, they tried the 100 ton containment dome first. This was a gas lift pump like the Sombrero. But they did not account for the formation of gas hydrates, although they must have known this would happen. The hydrates plugged the flow. This problem did not exist at Ixtoc because of the much lower pressure and higher temperature of the water.
Why did BP install the containment dome without any measures to prevent hydrates? And why did they put a 1" orifice in the 6" riser? There are several discussions of this orifice on the Oil Drum. You can find them by searching the site for posts by Jquest and windward. See some of my posts above also.
My answer is that BP wanted to appear to be doing something to get the oil and gas to the surface where it could be collected, but actually wanted to keep as much of it as possible underwater, where it couldn't be seen on the TV news. I also believe that is why they used so much dispersant. We will learn that these tactics caused far greater damage than would have resulted from forcing the oil and gas to the surface for collection or flaring.
Of course, there was no plan or equipment ready for handling the oil and gas at the surface either. But I don't think it would have taken three months to figure out how to do it, if they could have gotten the containment dome to work. They did manage to handle the oil and gas that came up from the last top cap.
It is important to note here a point I have made in previous posts. If a completely effective top cap can be installed quickly, perfectly sealed and no leaks, then there would be no need for a gas lift pump. The gas lift pump is for blowouts that have already entered the water, and there is no other way to quickly capture the oil and gas.
After Ixtoc, the O&G industry should have developed the gas lift pump to perfection, and had some of them ready for deployment. But they didn't want to spend the money, and the US government did not force them to do it because the MMS essentially belonged to the O&G industry. It will be hard to change this even after Macondo. The economy of the GOM and the US depends on oil production. Any obstacles to production such as moratoriums and stricter safety rules will be strongly opposed by many, and many of them will have clout.
However, as Rockman and others have made clear on the Oil Drum, most operators in the GOM and elsewhere would never have taken the risks that BP did at Macondo. It is even less likely now that any operator would do so.
A gas lift pump for extreme depths/pressures, where the temperatures are always near freezing, must be designed to handle gas hydrates. That is mainly what I have been proposing above. We already know that a gas lift pump will work, as long as it is not plugged. We can't reduce the pressure at these deep blowouts, so we must heat the flow in some way to prevent hydrate formation. A poster on the Oil Drum mentioned ultrasound as a possibility. I hadn't thought of that. Maybe microwaves would do it. I don't believe that the injection of inhibitors such as methanol or glycol would be as economic or effective as heating.
RE: use gas lift pump on BP Macondo blowout?
"...In the event of a future incident, mobilization to the field will start within days and the system will be fully operational within weeks..."
The main apparatus requires the connection of a "subsea containment assembly" to the existing BOP, as at Macondo. If all future blowouts occur at the BOP, and the BOP is still in good enough condition for this connection, so far so good. Until the connection is made and everything is hooked up, the blowout continues, maybe for "weeks".
Suppose the blowout is below the mudline, for example a damaged casing or a bad cement job. Connecting to the BOP won't help. The blowout is already entering the water elsewhere. Apparently the containment plan will be ready for this situation with the "capture caisson assembly". Sounds like an envelope around the leak with a riser to the surface. They intend to seal it to the seabed, to prevent water from entering.
Suppose this device is in place, and the riser is filled with oil and gas. The average density of the column inside the riser will be substantially less than that of the surrounding seawater. The differential pressure will be the greatest at the greatest depth, at the caisson. The seal to the seabed must withstand this differential pressure.
How much could it be? At Macondo, it would have been on the order of 400 psi. The seabed in most places is soft mud and sand for some considerable distance below the mudline. How deep must the caisson be sunk below the mudline to withstand possibly hundreds of psi of differential pressure? I don't know the answer, but I suspect it would be on the order of 100 feet.
I also suspect that it would not be easy to install the caisson because of this sealing requirement, and that it would take considerable time in any case. How large must the diameter of a round caisson be to cover a leak? If the oil and gas are coming up out of the seafloor, the leak cross section could be large.
The containment plan could require the construction of a set of caissons ranging in diameter from ten feet up to, say, 100 feet. They would pick the best size for the leak, but if 100 feet is not large enough, back to the shop for a bigger one. More time lost, and that billion dollars is going fast. In any case, the blowout continues until a big enough caisson is sunk deep enough for a seal, and the riser is connected on both ends.
The sealing problem would not exist with a gas lift pump. For the pump to operate, it requires a path for the seawater outside to flow into the capture vessel, which would be a cone or cylinder. The riser is attached to the top of the vessel. One aspect of the pump design is to keep the water flow to a minimum. The lower the water flow, the greater the driving force of the pump, because the more oil and gas and less water in the column, the lower the density of the column.
The diameter of the capture vessel would not have to be nearly as large as that of a caisson. When the pump is working, it will draw in the leaking oil and gas under it, and if necessary around it also, like a vacuum cleaner. Granted, the wider the cross section of the leak, the more water is entrained in the flow and the less effective the pump. But it still might work well enough on a leak with a cross section much wider than the capture vessel. Time for some studies and experiments. In fact, Jerome Milgram of MIT has already done a lot of work on the idea, but he quit in 1984 when funding stopped. See my 15 June post.
I doubt that it would take weeks to install a gas lift pump over a blowout. It does not require any undersea connections. No messing around with ROVS to remove damaged equipment and install a new stack. No need for all that equipment shown in the pdf. The pump is just a collection vessel and a riser, with a means for heating at the bottom if necessary. The pump would have to be assembled at the site and that would take some time, most likely days not weeks.
caltech69, regarding heating to prevent gas hydrates, I mentioned in an earlier post (30 June) that resistance heaters might work. They could be arranged as a screen with small passageways to minimize the flow of seawater into the system (although if the cross section of the leak is larger than the diameter of the capture vessel, these openings would also reduce the flow of oil and gas that is coming in from outside the vessel - details!). Heat transfer to the water would be very high with such a screen. It would probaly be easier to send electric current down to resistance heaters than it would be to send oxygen down to create a small fire in the flow - if such a fire is possible.
The gas lift pump probably requires at least some gas in the oil. If the leak was nothing but oil, which is also less dense than seawater, it still might work, and it would be an oil lift pump.