Changes

==Migration==

==Migration==

[[file:predicting-reservoir-system-quality-and-performance_fig9-14.png|thumb|{{figure number|1}}After <ref name=ch09r6>Berg, R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressures in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref>.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-14.png|thumb|{{figure number|1}}After Berg.<ref name=ch09r6>Berg, R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressures in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref>]]

Hydrocarbon migrates through an aquifer when it is “buoyed” upward due to AP caused by the density differential of the hydrocarbons and the formation water. The oil or gas migrates in filaments through the pore system of the aquifer as long as the [[buoyancy pressure]] (P_b) exceeds the capillary resistance of the water in the pore throats. This relationship is illustrated in the diagram below.

Hydrocarbon migrates through an aquifer when it is “buoyed” upward due to AP caused by the density differential of the hydrocarbons and the formation water. The oil or gas migrates in filaments through the pore system of the aquifer as long as the [[buoyancy pressure]] (P_b) exceeds the capillary resistance of the water in the pore throats. This relationship is illustrated in the diagram below.

==[[Buoyancy pressure]] profile==

==[[Buoyancy pressure]] profile==

[[file:predicting-reservoir-system-quality-and-performance_fig9-15.png|thumb|{{figure number|2}}From <ref name=Coalsonetal_1994>Coalson, E. B., S. M. Goolsby, and M. H. Franklin, 1994, Subtle seals and fluid-flow barriers in carbonate rocks, ''in'' J. C. Dolson, M. L. Hendricks, and W. A. Wescott, eds., Unconformity related hydrocarbons in sedimentary sequences: Rocky Mountain Association of Geologists (RMAG) Guidebook for Petroleum Exploration and Exploitation in Clastic and Carbonate Sediments, p. 45-58.</ref>. Courtesy RMAG.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-15.png|thumb|{{figure number|2}}From Coalson et al.<ref name=Coalsonetal_1994>Coalson, E. B., S. M. Goolsby, and M. H. Franklin, 1994, Subtle seals and fluid-flow barriers in carbonate rocks, ''in'' J. C. Dolson, M. L. Hendricks, and W. A. Wescott, eds., Unconformity related hydrocarbons in sedimentary sequences: Rocky Mountain Association of Geologists (RMAG) Guidebook for Petroleum Exploration and Exploitation in Clastic and Carbonate Sediments, p. 45-58.</ref> Courtesy RMAG.]]

When a reservoir has formed in a trap and has come to pressure equilibrium with the water in the aquifer, the pore pressure of the hydrocarbons at different depths in the reservoir plot along a steeper gradient than the water gradient. [[:file:predicting-reservoir-system-quality-and-performance_fig9-15.png|Figure 2]] shows this relationship.

When a reservoir has formed in a trap and has come to pressure equilibrium with the water in the aquifer, the pore pressure of the hydrocarbons at different depths in the reservoir plot along a steeper gradient than the water gradient. [[:file:predicting-reservoir-system-quality-and-performance_fig9-15.png|Figure 2]] shows this relationship.