Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Oil–oil and oil–source rock correlations

  | chapter = Oil–oil and oil–source rock correlations

  | frompg  = 8-1

  | frompg  = 8-64

  | topg    = 8-71

  | topg    = 8-66

  | author  = Douglas W. Waples, Joseph A. Curiale

  | author  = Douglas W. Waples, Joseph A. Curiale

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch08/ch08.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch08/ch08.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

Several Russian geoscientists as well as geochemists in the United States and Europe have addressed the question of the source(s) of oils in the prolific West Siberian basin. Peters et al.<ref name=ch08r41>Peters, K., E., Moldowan, J., M., Kontorovich, A., E., Huizinga, B., J., Moldowan, J., M., Lee, C., Y., 1994, [http://archives.datapages.com/data/bulletns/1994-96/data/pg/0078/0006/0850/0893.htm Multiple oil families in the West Siberian basin]: AAPG Bulletin, vol. 78, p. 893–909.</ref> present the results of a fully integrated [[oil–oil and oil–[[source rock]] correlation]] study involving numerous oils and possible [[source rocks]] in the basin. This case study examines the relationship between one of the West Siberian Basin oil families and its suggested source rock.

Several Russian geoscientists as well as geochemists in the United States and Europe have addressed the question of the source(s) of oils in the prolific West Siberian basin. Peters et al.<ref name=ch08r41>Peters, K. E., J. M. Moldowan, A. E. Kontorovich, B. J. Huizinga, J. M. Moldowan, and C. Y. Lee, 1994, [http://archives.datapages.com/data/bulletns/1994-96/data/pg/0078/0006/0850/0893.htm Multiple oil families in the West Siberian basin]: AAPG Bulletin, vol. 78, p. 893–909.</ref> present the results of a fully integrated [[oil–oil and oil–source rock correlation]] study involving numerous oils and possible [[source rocks]] in the basin. This case study examines the relationship between one of the West Siberian Basin oil families and its suggested source rock.

==Geological setting==

==Geological setting==

==Correlation process==

==Correlation process==

 

<gallery mode=packed heights=300px widths=300px>

<gallery mode=packed heights=200px widths=200px>

oiloil-and-oilsource-rock-correlations_fig8-53.png|{{figure number|1}}Stratigraphic section of the West Siberian basin. From Peters et al.;<ref name=ch08r41 /> courtesy AAPG.

oiloil-and-oilsource-rock-correlations_fig8-53.png|{{figure number|1}}Stratigraphic section of the West Siberian basin. From Peters et al.;<ref name=ch08r41 /> courtesy AAPG.

oiloil-and-oilsource-rock-correlations_fig8-54.png|{{figure number|2}}distribution of the C₂₇–C₂₉ regular steranes (left) and monoaromatic steroid hydrocarbons (right) for oils in the West Siberian basin. From Peters et al.;<ref name=ch08r41 /> courtesy AAPG.

oiloil-and-oilsource-rock-correlations_fig8-54.png|{{figure number|2}}distribution of the C₂₇–C₂₉ regular steranes (left) and monoaromatic steroid hydrocarbons (right) for oils in the West Siberian basin. From Peters et al.;<ref name=ch08r41 /> courtesy AAPG.

</gallery>

</gallery>

Peters et al.<ref name=ch08r41 /> examined 32 oil samples from this region, using a full assortment of elemental (sulfur), isotopic (δ¹³C of whole oil), and molecular data (biomarkers). In addition, source-based cluster analysis using sterane and diasterane distributions, tricyclic terpane distributions, and carbon isotope ratios was used to group the oils and prospective source rocks.

Peters et al.<ref name=ch08r41 /> examined 32 oil samples from this region, using a full assortment of elemental (sulfur), [[Wikipedia:Isotope geochemistry|isotopic]] (δ¹³C of whole oil), and molecular data (biomarkers). In addition, source-based cluster analysis using sterane and diasterane distributions, tricyclic terpane distributions, and carbon isotope ratios was used to group the oils and prospective source rocks.

Peters et al.<ref name=ch08r41 /> approached both the oil–oil and oil–source rock correlation aspects together, relying upon molecular and isotopic data accompanied by cluster analysis results. The distributions of regular steranes and monoaromatic steroid hydrocarbons (C₂₇– C₂₉) provided an excellent framework for the correlation. The oils (shown as solid circles in the figure below) form two distinct families according to these criteria: 26 oils fall in a group relatively depleted in the C₂₉ homolog, while six oils form a group relatively enriched in C₂₉. This two-family oil–oil classification is also consistent with whole-oil carbon isotope ratios as well as with other biomarker data.

Peters et al.<ref name=ch08r41 /> approached both the oil–oil and oil–source rock correlation aspects together, relying upon molecular and isotopic data accompanied by cluster analysis results. The distributions of regular steranes and monoaromatic steroid hydrocarbons (C₂₇– C₂₉) provided an excellent framework for the correlation. The oils (shown as solid circles in the figure below) form two distinct families according to these criteria: 26 oils fall in a group relatively depleted in the C₂₉ homolog, while six oils form a group relatively enriched in C₂₉. This two-family oil–oil classification is also consistent with whole-oil carbon isotope ratios as well as with other biomarker data.

==What this case study indicates==

==What this case study indicates==

The conclusion of Peters et al.<ref name=ch08r41 />) that the “low-C₂₉” oils are most likely sourced from the Bazhenov Formation is based upon isotopic and molecular data that are unaffected by maturity and alteration differences that the oils suffered after leaving the Bazhenov source rock. These changes caused variations in sulfur concentrations from less than 0.5% to greater than 2.0%. This case study emphasizes the importance of using source-distinctive biomarker and isotopic data to see through the changes wrought by differences in oil maturity and in-reservoir alteration.

The conclusion of Peters et al.<ref name=ch08r41 />) that the “low-C₂₉” oils are most likely sourced from the Bazhenov Formation is based upon [[Wikipedia:Isotope geochemistry|isotopic]] and molecular data that are unaffected by maturity and alteration differences that the oils suffered after leaving the Bazhenov source rock. These changes caused variations in sulfur concentrations from less than 0.5% to greater than 2.0%. This case study emphasizes the importance of using source-distinctive biomarker and isotopic data to see through the changes wrought by differences in oil maturity and in-reservoir alteration.

==See also==

==See also==

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

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

[[Category:Oil–oil and oil–source rock correlations]]

[[Category:Oil–oil and oil–source rock correlations]]