>I remember those articles, and I think you should post at least one of them, so we can brush-up on the subject.

Back in March 2008 I posted several articles on how pressure increases with depth, but after a certain point, the pressures can begin to drop. Oil and gas can therefore not only migrate up, but also down.

"The predicted overpressures at the centre of the Mako Trough are in reasonable agreement with measured and inferred overpressures in the Hod-I well (Fig. 12). In general, the overpressures are maximal in the DB unit [Upper and Lower Endrod] which is caused by the combination of low permeability and high porosity at deposition. The overpressures decrease upwards and downwards from the maximum overpressure zone. The overpressure decrease with depth is high enough to promote downward migration of hydrocarbons into the permeable basal unit and basement"


"As the marl sequences are the major source rock for hydrocarbons in the Neogene sediments and the overpressure maximum occurs exactly in this unit, the increase of overpressure has probably enhanced the primary migration considerably. Our modelling also shows that the overpressures decrease with depth in the deepest part of the basin, promoting a downward migration of hydrocarbons, enhancing the prospectivity of the deepest unit."

Of course some people on IV thought this idea was stupid:

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Oct. 20, 2008 (Bloomberg) -- A Gulf of Mexico oil field abandoned
by Exxon Mobil Corp. two years ago as no longer worth drilling
may turn out to be the biggest U.S. discovery in a decade.
The South Timbalier 168 project off the coast of Louisiana
may hold ``several billion barrels of oil,'' rather than the 500
million previously estimated, said James ``Jim Bob'' Moffett,
co-chairman of McMoRan Exploration Co., which is leading a
drilling effort at the field.