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  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

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The ease with which hydrocarbons move through the stratigraphic section is controlled by the petrophysical properties of the pore system, the mineralogy of the rock, and the properties of the hydrocarbons. These factors determine the preferential pathway of migration from high to low potential energy and are responsible for concentrating or dispersing the hydrocarbons.

The ease with which hydrocarbons move through the stratigraphic section is controlled by the petrophysical properties of the [[Pore system fundamentals|pore system]], the mineralogy of the rock, and the properties of the hydrocarbons. These factors determine the preferential pathway of migration from high to low potential energy and are responsible for concentrating or dispersing the hydrocarbons.

==Pore throats as sieves==

==Pore throats as sieves==

Pore throats act as molecular sieves, allowing particles smaller than the orifice to pass and retaining larger particles. If seals were uniformly composed of the same pore throats, they would be perfect seals for compounds larger than the pore throat apertures.

Pore throats act as molecular sieves, allowing particles smaller than the orifice to pass and retaining larger particles. If seals were uniformly composed of the same pore throats, they would be perfect seals for compounds larger than the pore throat apertures.

[[file:migration-of-petroleum_fig7-3.png|thumb|{{figure number|1}}.]]

[[file:migration-of-petroleum_fig7-3.png|thumb|{{figure number|1}}]]

==Hydrocarbon molecular size==

==Hydrocarbon molecular size==