Oil, oil everywhere, and not a drop to drink

General discussions of interest to readers and fans of Harlan Ellison.

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Oil, oil everywhere, and not a drop to drink

Postby Moderator » Wed Jun 09, 2010 10:05 am

Okay, everyone's running in circles deeming the oil spill in the gulf as a disaster, and there's no question that's an accurate assessment.

We've all heard the scenarios, ranging from significant damage to the Gulf and Gulf Coast (best scenario) all the way to total destruction of the Keys' reef and signficant damage to the Eastern Seaboard and Europe's Atlantic coast.

But here's something I haven't heard as an issue yet, and could make the whole thing immeasurably worse. (Peggy, if you're lurking keep me honest.)

When oil is pumped from the ground it creates a pocket. This pocket is typically backfilled by oil companies as they pull the crude out. It keeps the environment fairly stable, and reduces any subsidence which could cause the land above the pocket to collapse into the void.

With Deepwater Horizon destroyed, think of an underwater (and underground) balloon of oil being pressed down on by the immense weight of the mile of Gulf water on top. This explains why the pressure of the leak has been so strong.

Now. There are reports that the oil is now seeping from other places on the ocean floor. As the amount of oil in the field spews into the Gulf water, all of that equalization of presssure between the oil under the ground and the seawater pressing down upon it has been sent into disarray. The more oil that is pressed out, the greater the downward pressure on the seafloor. The daily outflow is estimated by the Flow Rate Technical Group to be between 500,000 and 800,000 gallons a day. Since BP has announced they are capturing 630,000 gallons a day we can assume the higher end of the estimate is more realistic. This is volume (and mass) that is not restored to the equilibrium under the sea floor, as it would be with an operational rig.

My fear is that a tipping point will occur between the pressure from above and the pocket below. What impact will this have on the sea floor (one can expect some form of subsidence), and would it be a gradual change or does it have the potential for a pseudo-seismic event of short duration. Could a large portion of the sea floor "cave in"? If it did, it would have two potential devastating effects: complete dispersal of the remaining undersea reservoir, and any shoreline damage as a result of such a seismic event.

Have I gone too far? Is this within the realm of possibility or is it fundamentally flawed from the physics standpoint? I deal with pings and pipes, so the above is based solely on High School Physics thirty years out of date.

Thoughts?
- I love to find adventure. All I need is a change of clothes, my Nikon, an open mind and a strong cup of coffee.

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Re: Oil, oil everywhere, and not a drop to drink

Postby swp » Wed Jun 09, 2010 10:23 am

Barber wrote:Okay, everyone's running in circles deeming the oil spill in the gulf as a disaster, and there's no question that's an accurate assessment.

agreed.
Barber wrote:My fear is that a tipping point will occur between the pressure from above and the pocket below. What impact will this have on the sea floor (one can expect some form of subsidence), and would it be a gradual change or does it have the potential for a pseudo-seismic event of short duration. Could a large portion of the sea floor "cave in"?

I suspect it is a gradual change, at the rate the field is being depleated, and ongoing. I thought it was salt water that they pumped in, since nothing else can match the sheer volume of what they pump out. The "cave in" is probably happening, just really really slowly.

Barber wrote:Have I gone too far?

Yes.
:-)
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Re: Oil, oil everywhere, and not a drop to drink

Postby Steve Evil » Thu Jun 10, 2010 2:19 am

Was it Frank who suggested that Jules Verne should fix the spill? I'm sure Captain Nemo would know what to do. . .

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Re: Oil, oil everywhere, and not a drop to drink

Postby Moderator » Thu Jun 10, 2010 7:07 am

Steve Evil wrote:Was it Frank who suggested that Jules Verne should fix the spill? I'm sure Captain Nemo would know what to do. . .



Sink all of BP's ships, no doubt.
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Re: Oil, oil everywhere, and not a drop to drink

Postby FrankChurch » Fri Jun 11, 2010 1:21 pm

Morning Joe was in Pensacola Beach, a beautiful white sand beach and they were harping on about how people need to visit the area, eat at restaurants, shop, enjoy themselves. They forget that Americans are the most frightened people on the planet. These are the people who refused to go to Europe during the Gulf War because they were afraid that Hussein might bomb a Paris eatery. It was complete fanaticism. Then you had 9/11, people signed on to Bush's dismantling of the freedoms we shared and went along with eight years of illegal uglyness.

Americans will stay away from the beaches in droves, sadly.

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Re: Oil, oil everywhere, and not a drop to drink

Postby David Loftus » Fri Jun 11, 2010 3:03 pm

Here's a video about what happens when a coffee spill occurs at BP headquarters:

http://www.youtube.com/watch?v=2AAa0gd7ClM
War is, at first, the hope that one will be better off; next, the expectation that the other fellow will be worse off; then, the satisfaction that he isn't any better off; and, finally, the surprise at everyone's being worse off. - Karl Kraus

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Re: Oil, oil everywhere, and not a drop to drink

Postby Ezra Lb. » Fri Jun 11, 2010 3:54 pm

We just wasted three hours!

:lol:

You know David the sad part is that video describes pretty much what seems to have happened.



Frank you exhibit what's called 'the bravery of being safely out of range'. I ride the Metro just about every day in a subway system with hundreds of access points, impossible to monitor completely, in the capitol city of the nation that is target numero uno for Islamic Jihad. You don't think I don't consider that sometimes when I'm standing on the platform at rush-hour?
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Re: Oil, oil everywhere, and not a drop to drink

Postby Peggy » Sat Jun 26, 2010 5:20 pm

Hey Steve,

First time on the fora since October, sorry for delayed reply.

Couple of basic issues with your description.

Barber wrote:With Deepwater Horizon destroyed, think of an underwater (and underground) balloon of oil being pressed down on by the immense weight of the mile of Gulf water on top. This explains why the pressure of the leak has been so strong.


Incorrect. Production is caused by reservoir pressure, not surface pressure. Reservoir pressure is developed by a variety of geophysical causes and tends to be 'trapped' in the reservoir by sealing rocks (such as shales). Hence why a reservoir sand at a deeper level can have a lower pressure than one at a higher level.

FYI, external pressure above the reservoir production zone is from 5000' of water but also the additional 13000' of earth on top of the reservoir. Neither contribute to oil production.

Barber wrote:When oil is pumped from the ground it creates a pocket. This pocket is typically backfilled by oil companies as they pull the crude out. It keeps the environment fairly stable, and reduces any subsidence which could cause the land above the pocket to collapse into the void.
...
My fear is that a tipping point will occur between the pressure from above and the pocket below. What impact will this have on the sea floor (one can expect some form of subsidence), and would it be a gradual change or does it have the potential for a pseudo-seismic event of short duration. Could a large portion of the sea floor "cave in"? If it did, it would have two potential devastating effects: complete dispersal of the remaining undersea reservoir, and any shoreline damage as a result of such a seismic event.


Oil companies sometimes "'backfill" the reservoir voidage caused by oil production with water or sometimes gas to maintain pressure, but that is primarily for recovery rather than structural support. See basic description in this wiki article on primary, secondary, and tertiary recovery. http://en.wikipedia.org/wiki/Oil_production

Now, I'm not a geologist or reservoir engineer, and don't know much about subsidence associated with oil production. So, I did a simple google search on the subject. One of the most severe cases reported in one article was in Long Beach (ironically), as much as 9 meters. http://pubs.usgs.gov/of/2003/of03-337/extraction.html

Now, in comparison to the 13000' (~3800 m), that's not a lot. I cannot imagine subsidence that would lead to complete dispersal of this reservoir since it is so deep.

Also - for those who don't understand basic reservoir geology - the oil is not in a pool below ground. It is trapped in tiny interstitial spaces in the rock and earth which prevents it suddenly escaping.

Cheers
Peggy
"And if you're like me, you need hope, coffee and melody..." - Robbie Seay Band, "New Day"

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Re: Oil, oil everywhere, and not a drop to drink

Postby FrankChurch » Sun Jun 27, 2010 11:37 am

Peggy, niceeee.

She told you Barber. Snicker.


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