Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Sedimentary basin analysis

  | chapter = Sedimentary basin analysis

  | frompg  = 4-1

  | frompg  = 4-94

  | topg    = 4-123

  | topg    = 4-94

  | author  = John M. Armentrout

  | author  = John M. Armentrout

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

==Identification problem==

==Identification problem==

Geochemical typing of an oil in a reservoir rock and its correlation to a probable source rock are used to determine the level of certainty or the confidence that an oil originated from a specific source. Oils from the East Breaks 160-161 field have been analyzed by Dow et al...<ref name=ch04r29>Dow, W., G., Yukler, M., A., Senftle, J., T., Kennicutt, M., C., IIArmentrout, J., M., 1990, Miocene oil source beds in the East Breaks basin, Flex-Trend, offshore Texas: Proceedings, Gulf Coast Section SEPM 9th Annual Research conference, p. 139–150.</ref> Those oils, one each from the ''Glob alt'' GA-3 reservoir and the ''Hyal B'' HB-2 reservoir, are very similar geochemically and closely resemble continental shelf oils of Louisiana and Texas. The East Breaks 160-161 ''Glob alt'' and ''Hyal B'' oils do not correlate with the Type 1-B oils<ref name=ch04r96>Thompson, K., F., M., Kennicutt, M., C., IIBrooks, J., M., 1990, Classification of offshore Gulf of Mexico oils and gas condensates: AAPG Bulletin, vol. 74, p. 187–198.</ref> of shelf-edge and continental slope reservoirs<ref name=ch04r29 />

Geochemical typing of an oil in a reservoir rock and its correlation to a probable source rock are used to determine the level of certainty or the confidence that an oil originated from a specific source. Oils from the East Breaks 160-161 field have been analyzed by Dow et al.<ref name=ch04r29>Dow, W. G., M. A. Yukler, J. T. Senftle, M. C. Kennicutt II, and J. M. Armentrout, 1990, Miocene oil source beds in the East Breaks basin, Flex-Trend, offshore Texas: Proceedings, Gulf Coast Section SEPM 9th Annual Research conference, p. 139–150.</ref> Those oils, one each from the ''Glob alt'' GA-3 reservoir and the ''Hyal B'' HB-2 reservoir, are very similar geochemically and closely resemble continental shelf oils of Louisiana and Texas. The East Breaks 160-161 ''Glob alt'' and ''Hyal B'' oils do not correlate with the Type 1-B oils<ref name=ch04r96>Thompson, K. F. M., M. C. Kennicutt II, and J. M. Brooks, 1990, [http://archives.datapages.com/data/bulletns/1990-91/data/pg/0074/0002/0000/0187.htm Classification of offshore Gulf of Mexico oils and gas condensates]: AAPG Bulletin, vol. 74, p. 187–198.</ref> of shelf-edge and continental slope reservoirs<ref name=ch04r29 />

==Miocene source?==

==Miocene source?==

[[file:sedimentary-basin-analysis_fig4-8.png|300px|thumb|{{figure number|1}}Traditional regional cross-section. Modified after Antoine et al.;<ref name=Antoine1974>Antoine, J. W., R. G. Ray, Jr., T. G. Pyle, and W. R. Bryant, 1974, Continental margins of the Gulf of Mexico, in C. A. Burk and C. L. Drake, eds., The Geology of Continental Margins: New York, Springer-Verlag, p. 683–693.</ref> courtesy Springer-Verlag.]]

Gross et al.<ref name=ch04r40>Gross, O., P., Hood, K., C., Wenger, L., M., Harrison, S., C., 1995, Seismic imaging and analysis of source and [[migration]] within an integrated hydrocarbon system study, northern Gulf of Mexico basin: Abstracts, 1st Latin American Geophysical conference, p. 1–4.</ref> suggest that the oil of the East Breaks–High Island area originated from either lower Tertiary mudstones or uppermost Jurassic mudstones (Figure 4-5). Philippi<ref name=ch04r74>Philippi, G., T., 1974, The influence of marine and terrestrial source material on the composition of petroleum: Geochim. Cosmochim. Acta, vol. 38., p. 947–966., 10., 1016/0016-7037(74)90067-2</ref> and Sassen et al.<ref name=ch04r85>Sassen, R., Tye, R., S., Chinn, E., W., Lemoine, R., C., 1988, Origin of crude oil in the Wilcox Trend of Louisiana and Mississippi: evidence of long range migration: Gulf Coast Assoc. Geological Societies Transactions, vol. 38, p. 27–34.</ref> present evidence for source potential for crude oil in the upper Paleocene to lower Eocene Wilcox Formation. If lower Tertiary Wilcox equivalent or uppermost Jurassic mudstones are the source for hydrocarbons in the East Breaks 160-161 field, then a migration avenue must exist through the salt that underlies the minibasin and generation-migration-accumulation must have been delayed until the trap formed approximately 1.2 Ma. In fact, alternative interpretations of salt distribution at the East Breaks 160-161 field suggest a salt weld with sediment-on-sediment below the minibasin rather than a salt floor (compare Figures 4-8 and 4-9). This suggests migration could have occurred from even older, more deeply buried source rocks.

==[[Migration]] pathways==

Data currently available preclude a precise correlation of the East Breaks 160-161 field oils with a specific source rock. Therefore, the petroleum system(s) charging the ''Glob alt'' reservoirs is speculative. However, the data do suggest that the hydrocarbons originate from more deeply buried thermally mature rocks than those encasing the reservoir and therefore vertical migration has occurred.

 

==Early Tertiary source?==

 

 

[[file:sedimentary-basin-analysis_fig4-9.png|thumb|500px|{{figure number|3}}Model of salt [[deformation]]. From Hall et al.;<ref name=Hall1993>Hall, D. J., B. E. Bowen, R. N. Rosen, S. Wu, and A. W. Bally, 1993, Mesozoic and early Cenozoic development of the Texas margin: a new integrated cross-section from the Cretaceous shelf edge to the Perdido fold belt: Selected Papers, Gulf Coast Section SEPM 13th Annual Research Conference, p. 21–31.</ref> courtesy Gulf Coast SEPM.]]

 

Gross et al.<ref name=ch04r40>Gross, O. P., K. C. Hood, L. M. Wenger, and S. C. Harrison, 1995, Seismic imaging and analysis of source and migration within an integrated hydrocarbon system study, northern Gulf of Mexico basin: Abstracts, 1st Latin American Geophysical conference, p. 1–4.</ref> suggest that the oil of the East Breaks–High Island area originated from either lower [[Tertiary]] mudstones or uppermost Jurassic mudstones ([[:file:sedimentary-basin-analysis_fig4-5.png|Figure 2]]). Philippi<ref name=ch04r74>Philippi, G. T., 1974, The influence of marine and terrestrial source material on the composition of petroleum: Geochim. Cosmochim. Acta, vol. 38., p. 947–966., 10., 1016/0016-7037(74)90067-2</ref> and Sassen et al.<ref name=ch04r85>Sassen, R., R. S. Tye, E. W. Chinn, and R. C. Lemoine, 1988, Origin of crude oil in the Wilcox Trend of Louisiana and Mississippi: evidence of long range migration: Gulf Coast Assoc. Geological Societies Transactions, vol. 38, p. 27–34.</ref> present evidence for source potential for [[crude oil]] in the upper Paleocene to lower Eocene Wilcox Formation. If lower Tertiary Wilcox equivalent or uppermost Jurassic mudstones are the source for hydrocarbons in the East Breaks 160-161 field, then a migration avenue must exist through the salt that underlies the minibasin and [[Petroleum generation|generation]]-[[migration]]-[[accumulation]] must have been delayed until the trap formed approximately 1.2 Ma. In fact, alternative interpretations of salt distribution at the East Breaks 160-161 field suggest a salt weld with sediment-on-sediment below the minibasin rather than a salt floor (compare [[:file:sedimentary-basin-analysis_fig4-8.png|Figures 1]] and [[:file:sedimentary-basin-analysis_fig4-9.png|3]]). This suggests migration could have occurred from even older, more deeply buried source rocks.

 

==Migration pathways==

Data currently available preclude a precise correlation of the East Breaks 160-161 field oils with a specific source rock. Therefore, the petroleum system(s) [[Calculating charge volume|charging]] the ''Glob alt'' reservoirs is speculative. However, the data do suggest that the hydrocarbons originate from more deeply buried thermally mature rocks than those encasing the reservoir and therefore vertical migration has occurred.

==Future work==

==Future work==

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

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

[[Category:Sedimentary basin analysis]]

[[Category:Sedimentary basin analysis]]