I have emailed them. I quote from the article and not from my...

I have emailed them. I quote from the article and not from my visionary ideas:

"This model's assumptions place some severe constraints on migration. The resulting logic can give insight into distruibution, not only in terms of volume but also the type of hydrocarbon. The assumption that faults are not conduits for migration and that vertical migration takes place by a combination of cross-fault migration and updip flow can significantly affect the type of hydrocarbon being preferentially migrated from an accumulation. This model predicts that spill from an accumulation is at the base-at the water level-at a cross-fault spillpoint. Later generated hydrocarbons are lighter, so they rise to the top of the trap. When the trap is full, earlier generted hydrocarbons are displaced at the spillpoint at the base of the trap. This displacement implies that a higher percentage of earlier generated hydrocarbons will probably move upward in a structure and that gas flushing will progress from ----DEEPER TO SHALLOWER TRAPS, SPILLING OIL UPWARD IN A STRUCTURE.---- This model, therefore, gives a very different prediction from one that assumes trap capacity is controlled by seal failure and hydrocarbons leave an accumulation either by direct migration up a fault or through an ianadequate seal. Seal failure models predict a higher probability of hydrocarbon leakage from the top of an accumulation, which preferential vertical migration of lighter hydrodcarbons." Urban S. Allan AAPG Bulletin 73-7 July 1989