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Engineering and Risk Assessment Failures at BP, Transocean and Halliburton

Its been 12 days since the explosion, and leaks are still poisoning the gulf with 200,000* gallons of oil per day. BPʻs attempts to utilize a containment dome have failed due to the formation of ice-like crystals that blocked the flow into the pipeline and made the container buoyant. Now they are talking about shooting garbage into the blowout preventer. BPʻs CEO keeps whining about how hard it is to utilize containment techniques at 5,000 feet, but it makes one wonder, if we know there is no proven technology to contain leaks at that depth, why is it legal to drill at 5,000 feet? If a single drill can do significant damage to most of the Gulf of Mexico, and there is no known way to contain it, how did it not have a legally mandated 3X redundant containment system with no single point of failure? What sort of risk modeling did BP, Transocean and Halliburton do? Iʻm not a mechanical engineer, but if someone told me a software system I was writing had the potential to destroy the Gulf of Mexico, you can bet it would be multiply redundant with no single point of failure and 100% test coverage. It doesnʻt seem like analogous precautions were made with this drill, but Iʻd be very interested to hear differing opinions from people with domain expertise.

BP, Transocean and Halliburton - Based on initial reports it appears your crappy engineering and shoddy risk assessment led to the worst environmental disaster in history. You can never pay enough to make up for this.

*... or two million, depending on who you ask.

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Comment by Brian on June 21, 2010 at 2:35am
One possibility nobody's raised is if the relief wells suffer accidents :P
Comment by Daniel Leuck on June 21, 2010 at 2:18am
Update: Oil companies and equipment suppliers are suing the federal government in an attempt to end the moratorium on deep water drilling despite the fact that 2.5 million gallons of oil continues to flow into the gulf, we still don't know what caused the accident and we still don't know how to stop it. Amazing.
Comment by Daniel Leuck on June 4, 2010 at 2:24pm
Lovely. So it would basically cover our state with the exception of the Big Island.
Comment by Gus Higuera on June 4, 2010 at 12:28pm
Check out this app, put your zip in and see how big the oil spill would be if it was in your backyard
Comment by Brian on June 4, 2010 at 9:08am
Given the depth of the reservoir I doubt you'll see the ground start to cave in. It is possible for the wellhead to completely fail though. Right now you basically have a leaking wellhead - if the casing/cement around the wellbore/head were to fail then you basically just have a hole in the ground with oil flowing out.

Once the pressure in an oil reservoir is no longer sufficient for it to come out of its own accord they will often pump water down into it since the oil floats on top. This is reportedly done in Ghawar and similar fields.
Comment by Jason on June 3, 2010 at 10:30am
That's interesting stuff. So, if there is that much pressure I assume the cavity begins to collapse as the oil is extracted. If the surrounding earth is rock and doesn't collapse then I guess at some point they have to pump the oil out? I guess that's why the call it a gusher! If the cavity remains I wonder if they pump sea water in to replace the oil?

So, I found this interesting youtube video apparently from someone who has been in the industry for 30 years and teaches booming. If it's half true then the clean up effort is flawed. Please, please, please, if you are sensitive to foul language do not watch this video because it would be offensive:
Comment by Brian on June 3, 2010 at 6:41am
Concrete density varies according to the type but is approximately twice as dense as seawater.

This is all speculation on my part, but based on what I've read it's likely the BOP activated and formed a partial seal. That may or may not have actually slowed the initial flow rate down to something barely detectable (or there may have been just too much confusion to realize what was going on following the sinking of the platform).

You have to remember the pressures are enormous though, if the wellhead is at least 5,000 psi - and it may be higher - 10,000 psi or so - then remember that as it shoots up the well its picking up sand and other sediment from the walls of the wellbore. If you swam across this 'leak' it would basically rip you apart.

We're not talking garden hose flows here - it's more like a sandblaster (industrial ones typically run somewhere from 1,000 to 7,000 psi). This means that the flow of material is slowly wearing away at the BOP and associated gear. For reference a water jet cutter like you use to cut steel is running somewhere around 30k to 90k psi.

So while originally it's likely the BOP partially operated, remember it had a dead battery, cutters which were not strong enough to cut through the joints (which make up 10% of the string) and also had hydraulic leaks and numerous design flaws.

At this point it's pretty trashed.
Comment by Jason on June 3, 2010 at 5:08am

Thanks for the details. So, I assume that because water compresses less than 1% it is still less dense than concrete at that depth? Anyway it's not an important point considering what you said about making a perfect seal. I did go to BP's website and found that they are actually drilling two relief wells that will intersect the main well. They state they will use the relief wells to pump concrete into and plug the main well.

Do you know if the BOP has a manual override cut off valve? It seems like it should have one considering what is happening now. Is the blow out valve just completely trashed?

It is just so painful to watch all that oil pour out into the open ocean.
Comment by Brian on June 3, 2010 at 12:02am

Water, even at that depth and temperature, is not very compressible.. less than 1%; so I presume you are preferring to the pressure. At that depth the water pressure is approximately 2,000 psi. There are wellhead's rated up to 20,000 psi. Given that it's unlikely BP would have knowingly used an insufficient BOP to drill a production well it's reasonable to assume it's within that range of 2-20k psi.

As far as dropping concrete blocks on top.. bear in mind that while the wellhead is approximately a mile down on the sea floor - the well actually goes another 18,000 or so feet down into the reservoir. If you just stacked stuff on top without getting a perfect seal it would just find its way out and leak - creating a potentially worse situation since you'd now have multiple points of egress and could potentially destabilize the surrounding seafloor - think of how a sinkhole is formed. You need to either have a perfect seal with a device that can hold back the pressure of the oil+gas or pump cement down into the well and plug it.
Comment by Jason on June 2, 2010 at 12:33pm
I'm concerned that BP's primary goal is not plugging the leak but salvaging the drilled hole and salvaging their access to the oil cavity. I also am no mechanical engineer and at 5,000 ft the pressures are incredible and I don't know what the density of water is at that depth. Is it equal to concrete? But, it seems if they really wanted to stop the leak they could. Why not blast that massive valve off and drop a huge block of concrete on top with a cavity inside? Is it because there is no crane big enough? I mean this is just off the top of my head. From the outside it looks like they are doing a salvage job. Is this because they won't be allowed to drill another hole into the cavity? Is it a gamble on their part that they can recover some profit that will over shadow the clean up bill?


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