A Petroleum Engineer's Explanation

OP:

Nice attemt to try to clean the sh** out of your food bowl.


Find new work!

reply to post by jonnboi99

my thoughts also...
the seabed is highly fragmented... using an nuke wont help....

Anyone heard of post-glacial rebound?

www.youtube.com...

reply to post by billyjack


Thanks for the great post and insight .
Why would the "company man" do this?

When the “company man” (the BP guy in charge) removed 16.5 #/gallon mud from the riser with 8.4 #.gallon sea water he immediately reduced the hydrostatic pressure 2000 psi & it was over.

What circumstances would require them to switch the drilling mud with sea water?
Considering a change to sea water would reduce the psi from the topside end of the riser.

Why do you think the blow out preventer failed? Is it not the job of the preventer to stop that if the pressure differential changes like it would have when sea water replaced the heavy drilling mud?
In your opinion, would an acoustic switch have prevented the blow out.

What are your thoughts?

Excellent thread Op, thanks for clearing this up.

I guess to sum it all up in a short form.

You pump a thicker goo down the pipe to stop the flow of the thinner goo.

However, as things are not sealed, the thicker goo is also flowing out the top, while you are trying to push the thinner goo back down the pipe.

If you don't pump the thick goo fast enough, the thinner goo will push it back out of the top of the pipe and the leak won't be stopped.

If you push it too fast, then it will create too much pressure, and make the leak worse way down below where the real problem lies.

So if I figured this correctly, at 1,800 Meter depth or around 5,000 - 6,000 ft, water pressure is around 1820 dbar or 2,639 PSI. If well pressure is 20,000 psi, then that is a considerable differential.

When you look at the deepest part of the ocean, the deep trenches, they are deeper than the well itself, which from what I am reading is 23,000 ft, while the Mariana Trench is 35,000 ft. Yet ocean pressure at 35,000 is at 16,000 psi, or 8 tons per square inch. You are saying that the oil pressure from this well is even higher than that.

www.seasky.org...

I don't see how concrete is all that effective of a material under those conditions.

reply to post by atlasastro


The head electronics technician for the rig who was on it when it exploded and was barely able to get off the rig and survived did a 60 Minutes interview a week or so back. See if you can find it. His interview is damning of BP and he goes into specific details about the BP exec who overruled the standing procedures used when capping the well. Watch that interview and it will become clear why the blowout occurred. It was all about rushing in order to save money.

reply to post by jtma508



Thanks mate, will do.

Tried to read all the responces and will try to address. The overall problem in the oil industry is that we have a generation of engineers that have been trained by accountants and bankers. In 1986 when the bottom fell out, oil companies were taken over by accountants. Accounts can't design, create or sell and in general are clueless about the revenue side of the income statement, but percieve themselves as geniuses concerning expenses. Their only solutions entail cutting costs, for the most part by laying off the work force. As a consequence the engineer that got raises, bonuses and promotions was the guy that saved money not the engineer that produced oil without killing people. I am sure this mental approach is what ultimately caused this disaster.

As far as the blow out all I have are field rumors.
1) They pumped a poor cement design that was pumped while the well was basically already blowing out although it had not hit the surface.
2) They didn't change out the pipe rams to the 7". Pipe rams are slotted to wrap around the diameter of pipe in the blowout preventer. The diameter of the drill pipe was 5 1/2" to 6". Prior to running the 7" casing the rams are supposed to be changed out to the new diameter. There has been talk about the BOP shear rams and others, but no one has mentioned the satus of the pipe rams.
3) Unless you could get the nuclear weapon way down the hole, I can only surmise it would crate a bigger disaster.
4) The bottom kill is easier once you are there and have a pipe to pump mud & cement through, I didn't mean to imply hitting the target is easy. I've taken "kicks" and seldom got hysterical if I had pipe on bottom, because I can take pressure measurments and calculate what it takes to kill the well and can control circulating out the "bubble".
5) I need to emphasize that all of the kill procedures must be accomplished with out exceeding the burst pressure of the casing in place. This is waht happened in Santa Barbara in 1969. That idiot Red Adair instead of taking measuements just tied onto the wellbore and started pumping in & exceeded the burst pressure of the casing. After that happens the only solution is the relief well.
6) Again, we don't need to worry about the earth moving. Oil comes from the tiny pore spaces between sand grains. This reservoir is 18,000' deep, even if there is slight compaction due to reduced bottom hole pressure causing the sand grains to get closer together it will not effect the seabed.
7) The large spill in the time frame and concentrations we are seeing is comparable to the one in Mexico from Ixtoc. I'm not aware of the long term effects, however oil naturally seeps into the gulf. Roberto Debaca recaulked his ships from the tar on the beaches in Port Isabelle in 1519.
8) I have no way to estimate what rate the blowout is occurring. We do measure rates accurately when we know the diameter of the pipe and have a pressure up stream, then we can calculate. With irregular diameters of escape and no flowing pressure estimates its anybody's guess. The area of the spill on the surface is no help. A quart of oil on your swimming pool will look like the Exxon Valdez.
9) The experts comments that are mindless prattle are many. Bill Nye really galled me when he proposed that the drilling mud will plate out closing the diameter of the pipe. Drilling mud is a highly sophisticated fluid. What someone told Nye was about a property of mud where it forms a filter cake against a permeable membrane. The clay particles in mud are too big to go into the tiny spaces between sand grains and will not penetrate into the formation and will plate out forming an impermeable barrier to keep the mud from dehydrating. If there's no permeable barrier the mud will not plate out. Since he didn't understand this he postulated that the mud would plate out against impermeable steel.
Most comments are on the edge where there is a little knowledge without understanding. Continued

Originally posted by jtma508
Watch that interview and it will become clear why the blowout occurred. It was all about rushing in order to save money.

Here it is jtma...



Very informative insight into the events leading up to the blowout and subsequent disaster.

They'd already "lost" $20M on the previous unsuccessful drill and were apparently pushing this operation in an attempt to recoup that "loss" on this operation ... despite the Numerous warnings and Expressed opposition by on-site personnel.

[speeling]

[edit on 30-5-2010 by 12m8keall2c]

Originally posted by rbilly001
I dont understand why everyone is saying this is an extinction event, its happened before and all though the environment is screwed it was not an extinction event. given time it will recover. Hopefully they will actually learn a few lessons here.

www.usatoday.com...

People are calling this an extinction level event (ELE) because many believe the measures being taken right now, and those that will follow, are failing, and will continue to fail. Many people believe that explosives will be used to try to plug the leak (especially if the DoD gets involved) and that the resulting explosion will not seal the leak, but will open up a gaping hole allowing the oil to surge out of the depths at the fastest rate possible.

Having the entire oil deposit (or at least 90% of it) rise to the surface when the pressure is released, wouldn't be conducive to life for marine life, and the circle of life requires that sea animals don't have their own ELE's.

There are those who say that even half of the deposit would never leave the ground due to it being suspended in sand. I maintain that it would, in fact, come out of the ground due to the vast pressures involved, and the unsettling truth of the specific gravity of oil. It will surface if they knock a huge hole in the ground trying to seal the leak. Some have mentioned small nukes. I see that ending in an epic fail.

When we read about Gulf of Mexico oil reaching Greenland, that'll be an indication that this oil will shut down the entire Atlantic fishing industry because the fish will all die off. When oil seals the surface, the water can not oxygenate. When the O2 levels drop on an entire ocean, what do you think follows?

I appreciate the oil engineer's perspective on this. It assures me that those in charge are going out of their way to make every wrong decision possible. If they open this thing up, an ELE is possible.

reply to post by werk71


Thanks for an alternative viewpoint from someone else who works in the field.

I have to wonder if the concrete well encasing technique is adequate for deep water wells. Sounds like it can and does work, but is a tricky process.

Why would BP play so loose and fast with the rules, or technological difficulties, of drilling such wells, with so much at stake.

Who is BP? Originally they were calling themselves Anglo Arab oil.

There is some amazing information at this website.

www.modernhistoryproject.org...

Are we looking at a major play in the world's balance of power?

Continued:
MSNBC had Matt Simmons & some guy with a pipeline consulting firm. Both have enough knowledge to be dangerous. One is a journalist and the other an MBA, in short neither has ever drilled a well or been on a location and handled a kick and I'm sure neither has taken differential equations.

Somebody asked why they displaced the mud in the riser with seawater. They were about to temporarily abandon the well & disconnect the riser so they didn't want to dump the mud in the ocean. They didn't know that this 5000' of mud was the only thing saving them from disaster.

The explsions were set off when gas hit the rig floor and the carbuerators of the diesel engines sucked up natural gas and ran away. Put your car in park & floor the accelerator, it will finally blow the engine. Do this with 2000 hp diesel engine and the effect is devastating.

A cement bond log is used to evaluate whether there is cement behind the pipe. I would be flabbergasted if they did not intend to run the log at some point, but it blew out before they had a chance. CBL's are pretty good at establishing if you don't have a good cement job, but are not completely dependable to establish that you do.

I am as frustrated by BP as anybody, because these kind of disasters effect everyone in the business. Like any large corporation, I am sure thay are very bureacratic and back to the opening paragraph their technical people are still mired in trying to save money. They are finally reporting that they are going to cut the riser out of the way. I really don't understand why this wasn't step one. With the riser gone at least they have a clean opening to work with and the spill is not spread over a mile in three parts of the riser. I'm not sure that if they just close the blow out preventers the casing is strong enough to withstand without bursting. If they can get vessels to float near enough to the wellbore, I'd get a coil tubing unit with a tubing conveyed perforating gun and stab into the well, go in to 15,000' & shoot holes in the 7" and start pumping mud to do a bottom kill. Sounds too simple so there must be something I'm missing that prohibits this far under the ocean or the lack of buoyancy of the ocean doesn't allow them to get close enough to the wellhead.

I am reading a lot...trying to understand the problems and procedures from the perspective of someone who knows less than nothing related to this event so I truly appreciate the input and insight of those in the know...I simply do NOT understand why no one "in power" is not on site closely monitoring the situation and reporting back to the locals, the rest of us,and even the world?

They have a freakin' Czar" and "Task Force" for every OTHER little booboo that pops up but this is all being left in the hands of an independent company to resolve?
They have "controls" in place when it comes to our money, insurances, and day to day life but NOTHING is even remotely in place to insure that this catastrophic cluster-f*** is being dealt with?
Color me stupid I guess.

The lack of consistancy,press that has access (and yes,I do understand that there is a job to be done and that more people create clutter nad confusion...) and honest reports and answers is disgusting and you'd think that by this time a more well thought out possible plan would have been considered?
They are "rat killin'" and "puttin' out fires" as the oil-guys around here are saying, not to say they aren't trying possible solutions but the scope of the damage,the situation,and the lack of apparent concern by TPTB is truly unsettling and frightening.
By now,everyone should KNOW the situation clearly,the possible REAL dangers ahead, and already have a PLAN in effect for the 'worst case..." I have read or seen NOTHING to demonstrate that this is happening.Mass evacuations? We've seen how well THAT lil' situation works...

I hope that the locals don't get fed up to the point of REALLY taking matters into their own hands and could we blame them if they did? These people are losing their way of life, livelihoods, jobs,and property values along with probably their personal freedom and health...I can guarentee that if Texas was involved in the mix it would be another story that would be taking place!

They are buying time over the long-weekend and simply sitting back making plans on how to continue the smoke-screen.

reply to post by billyjack


If it simply amounts to the foolishness and arrogance of accountants, which seems to be quite possible, then they certainly failed to do an adequate job of cost risk analysis.

Maybe the bigger problem is that the expense of deep water drilling as it currently stands is so high that they are running into a situation where this pursuit of deep water oil reservoirs is not economically feasible. Alternative energy sources and efficiency could be turning the oil industry into a thing of the past, with the easy to get cheap crude running out.

I think Halliburton's decision to relocate their corproate headquarters to the United Arab Emirates becomes even more significant.

reply to post by poet1b


To answer your question yes the reservoir pressure is higher than the normal gradient of seawater or fresh water. I am basing the 20,000 psi on the depth of the well & the fact that they had 16.5 #/gallon mud to control the well. If htere was not 16.5#/gallon mud all the way to the top of the reservoir then this estimate may be high. The reason one could have higher pressure than the seawater gradient around .433 psi/ft is due to the over burden weight of the ground itself. The sandstone was deposited millions of years ago and was buried between impermeable layers of shale and the fluids between the sand grains were trapped and could not escape. As more and more sand & shale buried the formation the weight of the earth itself started pressing on the trapped formation attempting to collapse the sand. The fluids that could not escape started compressing and the oil itself began holding up the earth. Since sand weighs 2.65 times as much as water the pressure exerted by the earth is substaially higher than water and if the sand cannot hold up the earth the fluid in the pore spaces will.

reply to post by atlasastro


If htere are 6 degrees of seperation in the world there are only 2 in the oilfiled. The "field" rumor is they had tools in the 7" that prevented the shear rams from working. Shear rams are steel designed to cut off anything in the blowout preventer and close. What no one has talked about are the pipe rams. I'd bet money that they didn't change out the pipe rams to the diameter of the casing. If this is the case it doesn't matter what closing acctuator you use. Electronic,hydraulic, mechanical or acoustic.

reply to post by HoaglandIsMyHero

Plagiarizing material is not cool. Especially when you put the links to where you got it and it matches your text word for word. That is just rubbing it in our face. use these next time

text here

reply to post by billyjack


Thanks for the reply. It seems clear to me that you have a excellent grasp of the subject. I have but a technical layman's grasp of the subject, which I am trying to improve upon, and not technical in this field.

They are finally reporting that they are going to cut the riser out of the way. I really don't understand why this wasn't step one. With the riser gone at least they have a clean opening to work with and the spill is not spread over a mile in three parts of the riser.

I have been wondering that myself. My reasoning is that they are afraid that they might only make the current release much worse. At this point they might have very little confidence in their technical people, and are reluctant to bring in outside people, who might eventually lead to them being very exposed on the legal end.

The reason I brought up the vast amounts of pressure we are talking about, is because I question the effectiveness of concrete at these pressures. In a nutshell, concrete is pretty much one dimensional when dealing with pressure, great under fairly stable compression, but not much else.

Originally posted by billyjack
reply to post by poet1b

 

To answer your question yes the reservoir pressure is higher than the normal gradient of seawater or fresh water. I am basing the 20,000 psi on the depth of the well & the fact that they had 16.5 #/gallon mud to control the well. If htere was not 16.5#/gallon mud all the way to the top of the reservoir then this estimate may be high. The reason one could have higher pressure than the seawater gradient around .433 psi/ft is due to the over burden weight of the ground itself. The sandstone was deposited millions of years ago and was buried between impermeable layers of shale and the fluids between the sand grains were trapped and could not escape. As more and more sand & shale buried the formation the weight of the earth itself started pressing on the trapped formation attempting to collapse the sand. The fluids that could not escape started compressing and the oil itself began holding up the earth. Since sand weighs 2.65 times as much as water the pressure exerted by the earth is substaially higher than water and if the sand cannot hold up the earth the fluid in the pore spaces will.

Also- at those depths the temperature is pretty high and that increases the pressure as well...

reply to post by Just Wondering



I did not plagiarize, if anything I forgot to use quotes. Why would I give the source so you can find it? It's an honest mistake the rest was my words summarizing the info linked.

Funny how you say nothing about how damning this post is regarding all the clues before the explosion. You must work for BP....