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Thread: To stop the oil build a huge underwater structure

  1. #1 To stop the oil build a huge underwater structure 
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    wouldnt that work?

    then get the oil from the structure?


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    What oil? It leaks again?


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  4. #3  
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    where are you?

    in usa its big news the oil is coming from ocean and wildlife is dieing in lousiana
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    They tried that huge heavy cap and have recovered a small fraction of the gusher. What else did you have in mind?
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  6. #5  
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    Quote Originally Posted by Holmes
    where are you?

    in usa its big news the oil is coming from ocean and wildlife is dieing in lousiana
    Few days ago a local TV said they stopped it by pumping mud into the hole or something like that.

    Edit:Yes, you are right, it failed. Sorry for interrupting your thread.
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  7. #6 Re: To stop the oil build a huge underwater structure 
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    Quote Originally Posted by Holmes
    wouldnt that work?

    then get the oil from the structure?
    Drilling a relief well is likely just as easy and has a better chance of success.
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    Quote Originally Posted by Lynx_Fox
    They tried that huge heavy cap and have recovered a small fraction of the gusher. What else did you have in mind?
    You mean the inverted funnel, right?

    It would be nearly impossible to cap it with weight. There is a minimum of 300 PSI differential pressure at that depth. There might be much more. You can get concrete that is a specific gravity around 2.4. Maybe heavier. It weighs about 150 lbs per cubic foot. Sea water is about 64 pounds per cubic foot. Differential is 86 pounds. That means you would have to have a concrete plug about 500 ft. high to have the weight to stop the leak, assuming the oil pressure is only the differential of water and oil at 5000 ft. I'll bet because the oil goes deep below the sea floor, the pressure is much higher.
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    The shut-in (no flow) pressure differential is estimated at about 5000 psig.
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  10. #9  
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    I'm no expert on oil engineering but I thought pipelines were designed with taps or on/off switches to actually turn off oil flow. Was this a semi complete pipe that had been sunk into an oil deposit? I think the drilling rig blew up didn't it? I assumed there were safety measures to prevent oil gushing from open wells.
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  11. #10  
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    Quote Originally Posted by cypress
    The shut-in (no flow) pressure differential is estimated at about 5000 psig.
    Wow...

    I expected maybe 1000 PSI, but I never expected that much.

    5000 PSI will be extremely hard to contain.

    How large of a hole are we talking about at that pressure?
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    The production casing is 7 - 5/8 inch inside diameter.

    Bradford, they were in the process of finishing installation of the production or inner most casing. After it is cemented into place then they pierce the casing in the production zone and finally install liners, seals known as packers, production tubing and two subsurface safety shutoff valves. They didn't get far enough along to install the valves. Until the valves are in place, pressure is held back by a column of heavy mud. One mistake that was made was to circulate out some of the heavy mud for lighter brine so they could better asses the poor cement job and figure out how to fix it. In retrospect it seems they should have abandoned the well given the number of issues they encountered.
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    Why no discussion of the methyl hydrates and the difficulties of trying to contain the rapid evaporation and expansion as it made it's way up the pipe.

    Does the drilling process in and of itself produce enough heat to evaporate and sublimate the methanol enough to trigger something like this mess? At the pressures involved it's probably pretty common for find large amounts.
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    Source temperatures in the producing reservoir are generally 200-300 F. Hydrates won't form until about 40-45 F. In addition high velocities prevent large crystals and they don't attach to the pipe walls. In low flow and intermittent flow situations glycol (antifreeze) or methanol is normally injected below the mudline to depress the critical temperature to about 30 F.
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  15. #14  
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    Quote Originally Posted by cypress
    Source temperatures in the producing reservoir are generally 200-300 F. Hydrates won't form until about 40-45 F. In addition high velocities prevent large crystals and they don't attach to the pipe walls. In low flow and intermittent flow situations glycol (antifreeze) or methanol is normally injected below the mudline to depress the critical temperature to about 30 F.
    So if I understand you correctly you've got a layer of deep but relatively warm oil overlaid by a layer of cold hydrates and finally the ocean. So once the oil starts pumping we pretty much know it's going to release an area of methane as the hydrates sublimate near and inside the pipe.
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    Not quite.

    Hydrocarbon becomes trapped in sandstone and other high porosity geologic formations by layers of fine silt and shale that are too dense to allow difusion through it. Faulting and salt domes aid generation of hydrocarbon traps by adding impermeable blockages. The hydrocarbon reservoir remains warm do to the depth (temperature rises as you bore deeper into the earth and compressive energy from tectonic movement. Above the reservoir is generally water filled porous rock and shale/silt layers also fairly warm.

    In the reservoir much of the light hydrocarbon is liquified due to high pressure, but there is generally a gas cap of methane and some light end near the top of the porous area. There is almost never any hydrates in the subsurface due to elevated temperatures. The sea floor and upper layer of silt can however hold vast volumes of methyl hydrates. If any is encountered we avoid it by selecting a drilling location away from hydrates since it is thermally unstable and causes no end of difficulty attempting to drill.

    You are correct to predict that the liquified gas flashes in the well bore and tubing on its path to the surface, partially cooling the fluid.
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  17. #16  
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    Perhaps I'm being naive here but isn't it rather foolish to embark on difficult oil drilling operations without having sufficient backup measures in place in case the worst should happen and a major leak or blowout occurs?
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    No, I think you have it right, the response after the fact has been poor.
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