Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: michael on 27/04/2008 12:56:49
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michael asked the Naked Scientists:
Is it likely that removing oil from the Earth, now for nearly 100 years and much of it under high pressure, make the planet unstable?
What do you think?
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No, because the oil resides in the porous spaces in sandstone, so the structure is still intact when the oil is removed.
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Correct answer - it is how I make a living. If I thought that what I did would in any way destabilize the earth as a whole I would not do it.
That said, removal of oil from a small location where the rocks above it are unstable does result in subsidence. IT IS NOT THE MAIN CAUSE OF SUBSIDENCE, THOUGH. Strictly speaking the subsidence is not because rock is deforming. It is because unconsolidated sands and muds are above the location where the oil occurs. Examples of this are Avery Island near New Iberia, Louisiana. This is an oil field located around a salt dome. The salt rising due to isostatic pressure produced Avery Island in the surrounding swamps in the first place. As the oil was produced, the wooden platforms on which the pumping units were installed began to sink into the swamp. The platforms are made of creosote-impregnated timber and pump jacks, usually of the design below, were placed on these platforms and oil pumped from the wells.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi38.photobucket.com%2Falbums%2Fe111%2Fgeezer69%2Fbeam_balanced.jpg&hash=f08559448c3758d9d4fd66d16d8d86a1)
As the platforms began to sink it became necessary to keep the jacks above water so new levels were added.
The largest problem faced due to fluid withdrawal is the result of water withdrawal. Houston gets most of its drinking water from unconsolidated aquifers. The problem has become so sever that the local governments have banded together to address the problem. For more information see http://geology.com/news/2007/01/subsidence-houston-is-sinking.html