Science a GoGo's Home Page Forums General Discussion Physics Forum Gulf of Mexico Tragedy

Thinkingabout the Oil Rig explosion in the Gulf Mexico last week. The difficulties in placing a cap over the leak.
The cap ultimately filling up with Clathrate crystals, which is basically Methane within ice crystals. One can understand the difficulties experienced by the Oil Companys, when you have an oil leak one mile below the surface
I started wondering just why or how, an oil rig tethered in the ocean could catch fire?
To my mind an Oil rig in the sea is less likely to catch fire than a land rig......or is it?

***My thoughts are
One land, Methane gas is dispersed into the atmosphere just as soon as it leaves the drill hole
In the sea, especially one mile underwater the bubble of Methane quickly grows larger and larger as it speeds up to the surface........its probable that it would follow the riser pipe, and even cling to it, (if the pipe was coated in oil) Meaning that the huge methane bubble would break the sea surface, in one go, covering the rig platform in Methane for a half a second...but long enough to get ignited by any electric motor/generator or tx radio on the rig.
So my thought is that Methane disperses on land but not in the sea.!!
Now there is a lot of Oil in the Artic, together with Clathrates, which can be seen to be bubbling on the sea surface continuously, by fishing boats etc.
Drilling in the Artic ocean should be banned until a safer technology is developed
Oil Spills in cold waters last much, much, longer!!

I think it would be wiser to ban coal mining everywhere. That causes much more fatal accidents than offshore oil rigs.

And while we're at it, let's ban driving cars, which would not only save millions of lives, but also help the environment.

Oh wait, all that coal, oil and cars are doing amazing good things for people.

The question is: were the firefighters acting through lack of care or lack of knowledge?

They cared to save lives, and perhaps the rig; but The ASFS might legitimately claim to have been unaware of the likely consequences of their efforts. The rig designers, on the other hand, would have been aware. In that case, one might think that the rig owners have a responsibility to (a) ensure that they, themselves, are fully apprised of all appropriate emergency procedures, and (b) ensure that the emergency services are up to speed.

Certain 'American oil workers' might prefer to avoid this question.

these oil rigs have a balancing system that transfers water
between the legs of the platform to try and keep the rig level
in heavy seas.

if someone opened a watertight access and water flowed in
the access this might be the reason that the platform tilted.

then if the automatic balancing system transfered water in the
other legs to compensate for the tilt , well it wouldnt take
long to sink.

I just thought about this , there may have also been oil pouring into one of the legs as it tilted.

anyway , Im not exactly sure how it works and I might be wrong.

still the fire crews should not be at fault.

but the designers of the vessel and the safety training of the vessels crew.

and it could be that the crew could not get to the access
because of the water being pumped onto the deck.

from the looks of the videos trying to do anything on that rig , even trying to catch a breath of air would be
hard to do.

the eleven who are missing must have been trying there best to save the vessel from sinking , they might have even
been down in a leg trying to fix or start some pump or something as it filled with water and possibly even oil.

they must be heros.

the deepwater horizon specs

a forum with some great pictures of the rig before and after.

close up shots of the rig before it sunk

Hey Mike

It looks like the first link I posted to the close ups
doesnt work any longer , but I found some even better quality shots.

better quality close up shots

theres also a video at the bottom of the page of a
Coast Guard SAR team doing a deck rescue off the rig.

Im not positive but I think there are 4 legs on the
Deepwater Horizon also.

I think I found out about the auto leveling by watching
a documentary on tv.

about a oil rig being tugged out to sea and then sunk using the system , and I think it said that the same system
would be used to level the rig in heavy seas.

Im not exactly sure if thats how it works though.

Mike

I suppose that if the flotation sections at the bottom
of the legs were welded closed and filled with nitrogen
gas.

even a extreme heat from a fire would not have caused it to
sink.

since the buoyant parts would be below water level.

and the buoyant parts could be isolated completely from the rest of the rig above , by having only beams connecting
between the buoyants and the upper structure.

but in this case it appears that that is not the case and
the tremendous heat may have buckled the many bulkheads that house the watertight access points rendering them non
functional.

and even small amounts of water or any substance that will burn trapped inside a watertight compartment would greatly pressurize the compartment due to heat transfer , possibly blowing the doors seal.

Im sure there will be an investigation into the sea worthiness of the vessel and its design and they will determine the reason why it sank.

and adjust the design appropriately.

my main gripe to this point is the emergency valving system
that should have been deplolyed at the begining that would
have closed the flow of oil at the sea floor.

and my absolute biggest gripe is that there is no pinch valve system just above the well casing that could pinch the casing and the draw pipe in such a disaster.

if there were such a system installed on the oil wells
then a rov would have closed this flow off within hours.

it is the bush adminstrations fault that this rig sank.

they lowered or removed safety measures in favor
of cheaper oil production.

now how many rigs are there that dont have these safety
measures in place that are opperating as we speak.

hundreds , thousands , ???

and to top off my fears , they are going to use a top hat
once again if the top kill does not work.

I see a picture on tv of a apparatus that has a large end
that tapers to a small end.

it will be entertaining to watch as they try to place the
top hat over the pressurized flow comming out of the pipe.

what they need is a 21 inch "T" and manuver the T over the flow
this way the flow can pass through the T as it is being placed.

at the top of the T there should be a large valve placed
they can have the pumping pipes attached to the horizontal
outlet of the T and it can be the size of the pumping pipes , then when the pumping pipes are connected
they can close the large valve at the top.

then either pump out the oil or pump in concrete throuh the horrizontal outlet,