High pressures in oil fields would have bled off if earth were old

Claim

The high pressures found in oil and gas wells is proof of a young earth. If the earth were old, the pressures would have bled off by now.

Creationists fail to appreciate that oil is capable of migrating/leaking from its original reservoir, whether due to permeable rock layers, or due to geological events that allow the oil to bleed out from the originally sealed reservoir.
Creationists also fail to appreciate the high viscosity of oil limits the rate with which it permeates through porous sedimentary rocks, especially shale, in that, according to Wszolek and Burlingame, "Some idea of the extremely slow speed of fluid motion to be expected can be gained by considering the movement of ground water at shallow depths in dense clays, classed as "impermeable." Under a moderate hydraulic gradient and a reasonable value of permeability for clay, we come up with flow speeds of ground water on the order of 2 to 3 million years per kilometer [3.2 to 4.8 million years per mile]. Yet the permeability of source shales of petroleum is rated at only one-thousandth as great as for clays tested in the surface environment" (p. 573).
Even if the logic were sound, it would say more about the age of the oil than the age of Earth. It is ridiculous to suppose that the oil formed concurrently with the Earth.
There is no reason the high pressure in some oil wells needs to have been there indefinitely. The earth is constantly changing, plate tectonics and other natural phenomena will over time relieve the pressure in some wells and increase it in others.
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Suppressed Evidence (The slow permeability of oil through shale isn't mentioned.)
Composition (if oil is old (which is part of the earth), earth has to be old)