Changes

Slug flow (or bulk phase flow) is generally accepted as the dominant mechanism of primary hydrocarbon migration. Within the [[source rock]], the volume of hydrocarbons produced from kerogen increases until a continuous mass forms (a slug) that has enough force to overcome the capillary forces of the largest pore throat network. At that time, the slug moves into the closest coarse-grained bed. Expulsion is preferentially upward because of the hydrocarbons' buoyancy, but it may be downward due to [[Petroleum generation|generation]] and compaction pressure if the pathway is less restrictive. Expulsion probably acts discontinuously, resulting in periodic slugs of migrating hydrocarbons. Broad compositional differences between the slug and those hydrocarbons generated from the kerogen appear to be due to preferential retention of large hydrocarbons by fine pores.

Slug flow (or bulk phase flow) is generally accepted as the dominant mechanism of primary hydrocarbon migration. Within the [[source rock]], the volume of hydrocarbons produced from kerogen increases until a continuous mass forms (a slug) that has enough force to overcome the capillary forces of the largest pore throat network. At that time, the slug moves into the closest coarse-grained bed. Expulsion is preferentially upward because of the hydrocarbons' buoyancy, but it may be downward due to [[Petroleum generation|generation]] and compaction pressure if the pathway is less restrictive. Expulsion probably acts discontinuously, resulting in periodic slugs of migrating hydrocarbons. Broad compositional differences between the slug and those hydrocarbons generated from the kerogen appear to be due to preferential retention of large hydrocarbons by fine pores.

[[file:migration-of-petroleum_fig7-6.png|300px|thumb|{{figure number|1}}Phase diagram. After Pepper.<ref name=ch07r10>Pepper, A., S., 1991, Estimating the petroleum expulsion behavior of [[source rocks]]: a novel quantitative approach, in England, W., A., Fleet, E., J., eds., Petroleum Migration: Geological Society Special Publication no. 59, p. 9–31.</ref> Copyright: Geological Society.]]

[[file:migration-of-petroleum_fig7-6.png|300px|thumb|{{figure number|1}}Phase diagram. After Pepper.<ref name=ch07r10>Pepper, A. S., 1991, Estimating the petroleum expulsion behavior of [[source rocks]]: a novel quantitative approach, in W. A. England, and E. J. Fleet, eds., Petroleum Migration: Geological Society Special Publication no. 59, p. 9–31.</ref> Copyright: Geological Society.]]

==Slug flow in secondary, tertiary, and remigration==

==Slug flow in secondary, tertiary, and remigration==