Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Formation fluid pressure and its application

  | chapter = Formation fluid pressure and its application

  | frompg  = 5-1

  | frompg  = 5-51

  | topg    = 5-64

  | topg    = 5-52

  | author  = Edward A. Beaumont, Forrest Fiedler

  | author  = Edward A. Beaumont, Forrest Fiedler

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

==Impact on petroleum geology==

==Impact on petroleum geology==

Pressure compartments have a significant impact on the distribution of oil and gas within a basin. Leonard<ref name=ch05r12>Leonard, R., C., 1993, Distribution of sub-surface pressure in the Norwegian Central Graben and applications for exploration, in Parker, J., R., ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref> lists ways pressure compartments affect elements of petroleum geology:

Pressure compartments have a significant impact on the distribution of oil and gas within a basin. Leonard<ref name=ch05r12>Leonard, R. C., 1993, Distribution of sub-surface pressure in the Norwegian Central Graben and applications for exploration, in J. R. Parker, ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref> lists ways pressure compartments affect elements of petroleum geology:

* [[Porosity]] loss due to compaction is less in overpressured and more in underpressured rocks than in normally pressured rocks.

* [[Porosity]] loss due to compaction is less in overpressured and more in underpressured rocks than in normally pressured rocks.

==Concentration of traps==

==Concentration of traps==

In many regional pressure compartments, hydrocarbon generation creates pressures great enough to fracture the top seal. Top-seal fracturing episodically releases pressure and fluids, including oil and gas, from the pressure compartment. Oil and gas tend to be trapped in the first reservoir-quality rock over leak points.<ref name=ch05r12 /> Leak points form where the top seal is shallowest because fracture pressure is lowest in the top seal at that point. Leak points also can occur where faults are reactivated during tectonic events.<ref name=ch05r7>Gaarenstroom, L., Tromp, R., A., J., de Jong, M., C., Brandenburg, A., M., 1993, Overpressures in the Central North Sea: implications for trap integrity and drilling safety, in Parker, J., R., ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref>

In many regional pressure compartments, hydrocarbon generation creates pressures great enough to fracture the top seal. Top-seal fracturing episodically releases pressure and fluids, including oil and gas, from the pressure compartment. Oil and gas tend to be trapped in the first reservoir-quality rock over leak points.<ref name=ch05r12 /> Leak points form where the top seal is shallowest because fracture pressure is lowest in the top seal at that point. Leak points also can occur where faults are reactivated during tectonic events.<ref name=ch05r7>Gaarenstroom, L., R. A. J. Tromp, M. C. de Jong, and A. M. Brandenburg, 1993, Overpressures in the Central North Sea: implications for trap integrity and drilling safety, in J. R. Parker, ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref>

==Compartment-associated traps==

==Compartment-associated traps==

[[file:formation-fluid-pressure-and-its-application_fig5-32.png|300px|thumb|{{figure number|3}}Schematic cross section of traps associated with pressure compartments. After Powley;<ref name=ch05r14>Powley, D. E., 1990, Pressures and hydrogeology in petroleum basins: Earth Science Reviews, vol. 29, p. 215–226.</ref> Copyright Earth Science Reviews]]

[[file:formation-fluid-pressure-and-its-application_fig5-32.png|300px|thumb|{{figure number|3}}Schematic cross section of traps associated with pressure compartments. After Powley;<ref name=ch05r14>Powley, D. E., 1990, Pressures and hydrogeology in petroleum basins: Earth Science Reviews, vol. 29, p. 215–226.</ref> Copyright Earth Science Reviews]]

The diagram ([[:file:formation-fluid-pressure-and-its-application_fig5-32.png|Figure 3]]) is a schematic [[cross section]] of traps associated with pressure compartments.<ref name=ch05r3>Bradley, J., S., Powley, D., E., 1995, [http://archives.datapages.com/data/specpubs/memoir61/ch01/0001.htm Pressure compartments in sedimentary basins], in Ortoleva, P., J., ed., Basin Compartments and Seals: [http://store.aapg.org/detail.aspx?id=748 AAPG Memoir 61], p. 3–26. </ref>

The diagram ([[:file:formation-fluid-pressure-and-its-application_fig5-32.png|Figure 3]]) is a schematic [[cross section]] of traps associated with pressure compartments.<ref name=ch05r3>Bradley, J. S., and D. E. Powley, 1995, [http://archives.datapages.com/data/specpubs/memoir61/ch01/0001.htm Pressure compartments in sedimentary basins], in P. J. Ortoleva, ed., Basin Compartments and Seals: [http://store.aapg.org/detail.aspx?id=748 AAPG Memoir 61], p. 3–26. </ref>

==See also==

==See also==

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Formation fluid pressure and its application]]

[[Category:Formation fluid pressure and its application]]