The rate of transport of hydrocarbons by buoyancy depends on the density contrast of the hydrocarbons with water and hydrocarbon column height. The rate of transport of large hydrocarbon masses is limited by the time it takes the mass to grow to a column height that can overcome capillary forces of barriers to [[Hydrocarbon migration|migration]]. Once a continuous thread of hydrocarbons connects two coarse-grained units through an intermediate fine-grained unit, the transfer of hydrocarbons from the lower unit to the upper is only limited by the permeability of the pathway.
+
The rate of transport of hydrocarbons by buoyancy depends on the density contrast of the hydrocarbons with water and [[hydrocarbon column]] height. The rate of transport of large hydrocarbon masses is limited by the time it takes the mass to grow to a column height that can overcome capillary forces of barriers to [[Hydrocarbon migration|migration]]. Once a continuous thread of hydrocarbons connects two coarse-grained units through an intermediate fine-grained unit, the transfer of hydrocarbons from the lower unit to the upper is only limited by the permeability of the pathway.