The results show that even at very low flow rates, viscous pressure drops are not negligible and that pressure gradients within phases can be substantially different from relative permeabilities at extreme saturations. The results also show that neglecting viscous pressure drops may lead to underestimating the capacity of a seal. The conditions at which a particular seal will leak are also defined. The method of characteristics solution is extended to include the effects of capillary pressures. The results of this research show that it is possible to classify seals into static seals and dynamic seals based on the flux rate from the source rock, the capillary pressure curves for the reservoir and the seal.
Static seals conform to the conventional theory.
Dynamic seals, on the other hand, can show substantially more trapping than static seals. In both cases, it is possible to associate a time scale to the accumulation and indicate explanations to several other features commonly observed in secondary migration.