I'm only talking of layers above the granite.
There have been instances of fields refilling over time in Oklahoma and the Gulf of Mexico.
Myths not reality. Enhanced oil recovery that uses additional methods is not the same as refilling.
, if a pervious layer is full and the migration route is semi-porous
I'm asking about the impervious layer on top, that then has additional oil layer above has of a drastic different quality, viscosity, ratios of heavies to lights, etc.
I don’t know that we will know the truth
I don't know that some will every recognize what is before them.
Methane hydrate litters the ocean floor. Plate induction would carry some (most?) of it under the adjoining plate. The methane hydrate would cook off quickly and rise to the bottom of the plate above. You now have a simple hydrocarbon in the presence of oxygen and under great heat and pressure. The basalt would cook off more slowly and rise as granite next.
There is your oil layer and impervious layer and a source of micro-fossils.
If this is correct the entire hydrocarbon system is naturally recycling itself over geologic time.