‘Twould seem we are “talking past” each other here. That’s OK.
I do not argue that O&G can be extracted from non-porous/impermeable formations (basalt, granite, etc). I do posit that O&G migrate to ‘production’ formations (sedimentary) by virtue of both sub-surface pressures, tectonic convection and gravity.
To understand the mechanics one could always look to aquifers, salt-domes and brine-formations. Nature abhors a vacuum; porosity SHALL be filled.
To this date in time, we have extracted more petro-hydrocarbons from the Earth than can be accounted for by the estimated carbon-based lifeform population (pre-historic life, fossiuls, dinosaurs) or the Flood. (To my understanding, those are mutually exclusive and, thereby, not a “combinable” total.)
What then is the source of our on-going production?
Not true. There are still billions of barrels trapped within the source rocks, hence the developing shale plays around the world. It is similar thinking to gold deposits. The placer deposits are what have “escaped” from the Mother Lode. Conventional oil and gas reservoirs are like the placer deposits. What we are tapping now in the Eagle Ford, Bakken, etc. is the Mother Lode. Go out in the Gulf of Mexico and look at the massive clouds of algae in the water. All of it eventually dies and what isn’t consuming by critters falls out into the bowels of the basin to become the future source rocks in a few million years, once they are buried down to 10,000’ or so.