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Originally Posted by redpoint5
"Oil window", in that context seems to suggest there is a max temperature that oil or gas can be extracted. It doesn't suggest what is sensitive to temperatures above that, or what those max temperatures are.
Temperature rises surprisingly quickly as depth increases. Perhaps the dry and abandoned holes could be repurposed into geothermal electricity generation plants?
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It will be a combination of bottomhole temp. and pressure together.
All Gulf of Mexico wells, 20,000-28,000-feet ( True Vertical Depth ), producing oil are at less than 300-F.
Deeper wells are producing natural gas.
An onshore, Bertha No.1 well in Oklahoma, at 31,441-feet TVD, was @ 24,850-psi, and 475-F, and produced only liquid sulfur.
The petroleum geologist elected to complete the well @ 13,000-feet, and it produced natural gas for awhile before playing out.
A $7,000,000 'ultra-deep dry hole.'
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Carbonate rock is a VERY good thermal insulator. The thickness of the crust shields the formation from the heat below, which statistically would be outside the 'oil window'. ( 1,800-F ( 1,000-C ) at below the crust )
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wattsupwithat.com is good about parsing out what the actual 'depth' of a well is exactly.
A 40,000-foot well can have: 11,000-feet of actual vertical depth, plus 29,000-feet of slant-drilled horizontal 'depth.'
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Also, if you look at all the vertical cross-sections of the well bore, you notice that everything is sedimentary, or mild-metamorphic rock.
Formerly continental, continental shelf, or sea floor, which was buried and then subducted during tectonic activity.
Virtually all the petroleum and gas is of terrestrial, or near-terrestrial origin.
The ocean floor has been recycled and renewed at least 24-times since Earth formed.