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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 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.

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 [[Hydrocarbon migration|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 pressure==

==Pore pressure==

Differences in pore fluid overpressure determine the potential, general direction, and rate of fluid flow. For hydrocarbons, the force of buoyancy must be added. The spatial distribution of pressure differentials interacts with permeability and capillarity to determine the flow rates along multiple migration pathways. Perfect seals—ones that don't leak at all—rarely occur. Pressure minimums are a perfect seal. When all the forces acting on a hydrocarbon mass are resolved and a local minimum in gradient field occurs, the hydrocarbons will remain in the minimum as long as it exists. There is no migration out of that minimum.

Differences in pore fluid overpressure determine the potential, general direction, and rate of fluid flow. For hydrocarbons, the force of buoyancy must be added. The spatial distribution of pressure differentials interacts with permeability and capillarity to determine the flow rates along multiple [[Hydrocarbon migration|migration]] pathways. Perfect seals—ones that don't leak at all—rarely occur. Pressure minimums are a perfect seal. When all the forces acting on a hydrocarbon mass are resolved and a local minimum in gradient field occurs, the hydrocarbons will remain in the minimum as long as it exists. There is no migration out of that minimum.

==Phase changes==

==Phase changes==