Changes

==Geologic setting==

==Geologic setting==

[[file:petroleum-systems_fig3-7.png|thumb|300px|{{figure number|1}}From Cornford.<ref name=ch03r3 /> Burial history chart.]]

[[file:petroleum-systems_fig3-7.png|thumb|300px|{{figure number|1}}Burial history chart. From Cornford.<ref name=ch03r3 />]]

This petroleum system formed in sedimentary rocks deposited in a failed rift system in the North Sea between Great Britain, Norway, and Denmark. The prerift rocks are mostly underburden rocks and are not involved in this petroleum system except as reservoir rocks for a minor amount of petroleum. The synrift sedimentary section contains the source rock. The reservoir rock, seal rock, and overburden rock were deposited during the postrift period of sedimentation.

This petroleum system formed in sedimentary rocks deposited in a failed rift system in the North Sea between Great Britain, Norway, and Denmark. The prerift rocks are mostly underburden rocks and are not involved in this petroleum system except as reservoir rocks for a minor amount of petroleum. The synrift sedimentary section contains the source rock. The reservoir rock, seal rock, and overburden rock were deposited during the postrift period of sedimentation.

==Petroleum system map==

==Petroleum system map==

[[file:petroleum-systems_fig3-8.png|300px|thumb|{{figure number|2}}Modified from Cornford.<ref name=ch03r3 />]]

[[file:petroleum-systems_fig3-8.png|300px|thumb|{{figure number|2}}Petroleum system map. Modified from Cornford.<ref name=ch03r3 />]]

The petroleum system map in [[:file:petroleum-systems_fig3-8.png|Figure 2]] shows the pod of active source rock and the oil and gas [[accumulation]]s that were charged by this same pod of active source rock; all are within the geographic or known extent of the system. Most accumulations for the Mandal-Ekofisk(!) overly the active source rock, and the gas/condensate fields overlie the most mature source rock.

The petroleum system map in [[:file:petroleum-systems_fig3-8.png|Figure 2]] shows the pod of active source rock and the oil and gas [[accumulation]]s that were charged by this same pod of active source rock; all are within the geographic or known extent of the system. Most accumulations for the Mandal-Ekofisk(!) overly the active source rock, and the gas/condensate fields overlie the most mature source rock.

==Petroleum system cross section==

==Petroleum system cross section==

[[file:petroleum-systems_fig3-9.png|thumb|300px|{{figure number|3}}Modified from Cornford.<ref name=ch03r3 />]]

[[file:petroleum-systems_fig3-9.png|thumb|300px|{{figure number|3}}Petroleum system cross section. Modified from Cornford.<ref name=ch03r3 />]]

The petroleum system [[cross section]] in [[:file:petroleum-systems_fig3-9.png|Figure 3]] shows migration pathways and the spatial relation of the active source rock to the reservoir rocks. This section trends longitudinally (see [[:file:petroleum-systems_fig3-8.png|Figure 2]] for location) along the Central Graben and shows the vertical migration path from the active source rock through the Cretaceous rocks and horizontally along the basal Paleogene reservoir rocks until it [[Accumulation|accumulates]] in various traps. The underburden rock is pre-Late Jurassic in age and is not involved in the petroleum system except as minor reservoir rocks and where the Permian salt (Zechstein Group) creates diapirs that form petroleum traps and migration paths in fractured chalk.

The petroleum system [[cross section]] in [[:file:petroleum-systems_fig3-9.png|Figure 3]] shows migration pathways and the spatial relation of the active source rock to the reservoir rocks. This section trends longitudinally (see [[:file:petroleum-systems_fig3-8.png|Figure 2]] for location) along the Central Graben and shows the vertical migration path from the active source rock through the Cretaceous rocks and horizontally along the basal Paleogene reservoir rocks until it [[Accumulation|accumulates]] in various traps. The underburden rock is pre-Late Jurassic in age and is not involved in the petroleum system except as minor reservoir rocks and where the Permian salt (Zechstein Group) creates diapirs that form petroleum traps and migration paths in fractured chalk.

==Petroleum system events chart==

==Petroleum system events chart==

[[file:petroleum-systems_fig3-11.png|thumb|300px|{{figure number|5}}Modified from Cornford.<ref name=ch03r3 />.]]

[[file:petroleum-systems_fig3-11.png|thumb|300px|{{figure number|5}}Events chart. Modified from Cornford.<ref name=ch03r3 />.]]

An events chart indicates when the essential elements and processes took place to form a petroleum system, the critical moment, and the preservation time. In [[:file:petroleum-systems_fig3-11.png|Figure 5]], the source rock is the Upper Jurassic to Lower Cretaceous Mandal Formation, which was deposited as the rift formed. Most overburden rock of Cretaceous to Cenozoic age was deposited after the rift formed. The seal rock ranges from Permian to Neogene and consists of halite, shale, and chalk. Based on volume of petroleum, the Permian to Jurassic reservoir rocks are least important; the most important reservoir rocks are Late Cretaceous to early Paleogene in age. Most traps were created as the rift formed and filled through structural movement and halokenesis. Petroleum generation-migration-[[accumulation]] occurred from just over 100 Ma to the present day. The critical moment, or peak generation, is at 30 Ma.

An events chart indicates when the essential elements and processes took place to form a petroleum system, the critical moment, and the preservation time. In [[:file:petroleum-systems_fig3-11.png|Figure 5]], the source rock is the Upper Jurassic to Lower Cretaceous Mandal Formation, which was deposited as the rift formed. Most overburden rock of Cretaceous to Cenozoic age was deposited after the rift formed. The seal rock ranges from Permian to Neogene and consists of halite, shale, and chalk. Based on volume of petroleum, the Permian to Jurassic reservoir rocks are least important; the most important reservoir rocks are Late Cretaceous to early Paleogene in age. Most traps were created as the rift formed and filled through structural movement and halokenesis. Petroleum generation-migration-[[accumulation]] occurred from just over 100 Ma to the present day. The critical moment, or peak generation, is at 30 Ma.