Changes

==Geologic setting==

==Geologic setting==

[[file:petroleum-systems_fig3-12.png|left|thumb|{{figure number|1}}From Bird.<ref name=ch03r2 />]]

[[file:petroleum-systems_fig3-12.png|left|thumb|{{figure number|1}}Ellesmerian(!) petroleum system geographic extent. From Bird.<ref name=ch03r2 />]]

The North Slope evolved from a passive continental margin to a foredeep during the Jurassic. Prior to the Jurassic, Paleozoic and Mesozoic strata were deposited on a passive continental margin. They consist of Carboniferous platform carbonate rocks and Permian to Jurassic shelf to basinal siliciclastic rocks. The passive margin converted to a foredeep during the Jurassic and Cretaceous when it collided with an ocean island arc. The foredeep began to fill with sediments in the Middle Jurassic and continues to do so.

The North Slope evolved from a passive continental margin to a foredeep during the Jurassic. Prior to the Jurassic, Paleozoic and Mesozoic strata were deposited on a passive continental margin. They consist of Carboniferous platform carbonate rocks and Permian to Jurassic shelf to basinal siliciclastic rocks. The passive margin converted to a foredeep during the Jurassic and Cretaceous when it collided with an ocean island arc. The foredeep began to fill with sediments in the Middle Jurassic and continues to do so.

The foredeep basin fill consists of orogenic sedimentary materials eroded from the nearby ancestral Brooks Range that were deposited as a northeasterly prograding wedge of non-marine, shallow marine, basin-slope, and basin conglomerates, sandstones, and mud-stones.

The foredeep basin fill consists of orogenic sedimentary materials eroded from the nearby ancestral Brooks Range that were deposited as a northeasterly prograding wedge of non-marine, shallow marine, basin-slope, and basin conglomerates, sandstones, and mud-stones.

[[file:petroleum-systems_fig3-13.png|thumb|{{figure number|2}}From Bird.<ref name=ch03r2 />]]

[[file:petroleum-systems_fig3-13.png|thumb|{{figure number|2}}thermal maturity of the two main Ellesmerian(!) petroleum system source rocks, the Shublik Formation and the Kingak Shale. From Bird.<ref name=ch03r2 />]]

==Petroleum system map==

==Petroleum system map==

[[:file:petroleum-systems_fig3-12.png|Figure 1]] shows the Ellesmerian(!) petroleum system geographic extent. The limit is determined by the extent of the contiguous active source rock and the related petroleum accumulations.

[[:file:petroleum-systems_fig3-12.png|Figure 1]] shows the Ellesmerian(!) petroleum system geographic extent. The limit is determined by the extent of the contiguous active source rock and the related petroleum accumulations.

[[file:petroleum-systems_fig3-14.png|left|thumb|{{figure number|3}}From Bird.<ref name=ch03r2 />]]

[[file:petroleum-systems_fig3-14.png|left|thumb|{{figure number|3}}Major structural-stratigraphic elements, the occurrence of oil fields, elevation of selected vitrinite reflectance values, and reflectance isograds. From Bird.<ref name=ch03r2 />]]

==Petroleum system maturity map==

==Petroleum system maturity map==

The cross section of the Ellesmerian(!) petroleum system ([[:file:petroleum-systems_fig3-14.png|Figure 3]]) shows major structural-stratigraphic elements, the occurrence of oil fields, elevation of selected vitrinite reflectance values, and reflectance isograds. For the location, refer to [[:file:petroleum-systems_fig3-12.png|Figure 1]].

The cross section of the Ellesmerian(!) petroleum system ([[:file:petroleum-systems_fig3-14.png|Figure 3]]) shows major structural-stratigraphic elements, the occurrence of oil fields, elevation of selected vitrinite reflectance values, and reflectance isograds. For the location, refer to [[:file:petroleum-systems_fig3-12.png|Figure 1]].

[[file:petroleum-systems_fig3-15.png|thumb|{{figure number|4}}From Bird.<ref name=ch03r2 />]]

[[file:petroleum-systems_fig3-15.png|thumb|{{figure number|4}}Analysis of the burial history chart of the Inigok 1 well. From Bird.<ref name=ch03r2 />]]

==Burial history chart==

==Burial history chart==

Analysis of the burial history chart of the Inigok 1 well ([[:file:petroleum-systems_fig3-15.png|Figure 4]]) and other burial history charts indicates peak petroleum generation (the critical moment) probably occurred in Late Cretaceous time (approximately 75 Ma) in the western North Slope and in early Tertiary time (approximately 50 Ma) in the central and eastern part of the North Slope. Also, note the large increase in the rate of sedimentation during the Early Cretaceous.

Analysis of the burial history chart of the Inigok 1 well ([[:file:petroleum-systems_fig3-15.png|Figure 4]]) and other burial history charts indicates peak petroleum generation (the critical moment) probably occurred in Late Cretaceous time (approximately 75 Ma) in the western North Slope and in early Tertiary time (approximately 50 Ma) in the central and eastern part of the North Slope. Also, note the large increase in the rate of sedimentation during the Early Cretaceous.

[[file:petroleum-systems_fig3-16.png|left|thumb|{{figure number|5}}(left) From Seifert et al.<ref name=Seifertetal_1980>Seifert, W. K., J. M. Moldowan, and R. W. Jones, 1980, Application of biological marker chemistry to petroleum exploration: Proceedings of the 10th World Petroleum Congress, Bucharest, p. 425-440</ref> Courtesy World Petroleum Conference. (right) From Sedivy et al.<ref name=ch03r9>Sedivy, R., A., Penfield, I., E., Halpern, H., I., Drozd, R., J., Cole, G., A., Burwood, R., 1987, Investigation of source rock–crude oil relationships in the northern Alaska hydrocarbon habitat, in Tailleur, I., Weimer, P., eds., Alaskan North Slope Geology: Pacific Section SEPM Book 50, p. 169–179.</ref> Courtesy Pacific Section of SEPM.]]

[[file:petroleum-systems_fig3-16.png|left|thumb|{{figure number|5}}(left) Biological marker analysis. From Seifert et al.<ref name=Seifertetal_1980>Seifert, W. K., J. M. Moldowan, and R. W. Jones, 1980, Application of biological marker chemistry to petroleum exploration: Proceedings of the 10th World Petroleum Congress, Bucharest, p. 425-440</ref> Courtesy World Petroleum Conference. (right) Carbon isotopic composition comparisons. From Sedivy et al.<ref name=ch03r9>Sedivy, R., A., Penfield, I., E., Halpern, H., I., Drozd, R., J., Cole, G., A., Burwood, R., 1987, Investigation of source rock–crude oil relationships in the northern Alaska hydrocarbon habitat, in Tailleur, I., Weimer, P., eds., Alaskan North Slope Geology: Pacific Section SEPM Book 50, p. 169–179.</ref> Courtesy Pacific Section of SEPM.]]

==Oil-source rock correlation==

==Oil-source rock correlation==

Biological marker analysis ([[:file:petroleum-systems_fig3-16.png|Figure 5A]]) from the main reservoir rock, Sadlerochit Group, of Prudhoe Bay field shows that the oil originated from the Shublik Formation, the Kingak Shale, and the Hue Shale. Carbon isotopic composition comparisons ([[:file:petroleum-systems_fig3-16.png|Figure 5B]]) indicate that Shublik and Kingak share similar ¹³C values with oil from the Prudhoe Bay field, whereas the Hue Shale does not.

Biological marker analysis ([[:file:petroleum-systems_fig3-16.png|Figure 5A]]) from the main reservoir rock, Sadlerochit Group, of Prudhoe Bay field shows that the oil originated from the Shublik Formation, the Kingak Shale, and the Hue Shale. Carbon isotopic composition comparisons ([[:file:petroleum-systems_fig3-16.png|Figure 5B]]) indicate that Shublik and Kingak share similar ¹³C values with oil from the Prudhoe Bay field, whereas the Hue Shale does not.

[[file:petroleum-systems_fig3-17.png|thumb|{{figure number|6}}From Bird.<ref name=ch03r2 />]]

[[file:petroleum-systems_fig3-17.png|thumb|{{figure number|6}}Events chart for the Ellesmerian(!) petroleum system. From Bird.<ref name=ch03r2 />]]

==Petroleum system events chart==

==Petroleum system events chart==