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Oil correlation case history: West Siberian basin (view source)
Revision as of 16:40, 16 June 2014
, 16:40, 16 June 2014→Correlation process
Several possible source rocks in the basin show steroid carbon-number distributions similar to those of one of the oil families in [[:file:oiloil-and-oilsource-rock-correlations_fig8-54.png|Figure 2]]. In particular, all the Bazhenov Formation samples (uppermost Jurassic) plot adjacent to the oil family that is relatively lean in the C<sub>29</sub> homolog. Other rock samples that also plot with this family in these ternary diagrams do not show valid oil-source correlations using other biomarker and isotope parameters.
Several possible source rocks in the basin show steroid carbon-number distributions similar to those of one of the oil families in [[:file:oiloil-and-oilsource-rock-correlations_fig8-54.png|Figure 2]]. In particular, all the Bazhenov Formation samples (uppermost Jurassic) plot adjacent to the oil family that is relatively lean in the C<sub>29</sub> homolog. Other rock samples that also plot with this family in these ternary diagrams do not show valid oil-source correlations using other biomarker and isotope parameters.
[[file:oiloil-and-oilsource-rock-correlations_fig8-55.png|thumb|300px|{{figure number|3}}Distributions of homohopanes by carbon number (C<sub>31</sub>–C<sub>35</sub>) for bitumens from the Bazhenov Formation are essentially identical to those for the low-C<sub>29</sub>-sterane oil family. Modified.]]
[[file:oiloil-and-oilsource-rock-correlations_fig8-55.png|thumb|300px|{{figure number|3}}Distributions of homohopanes by carbon number (C<sub>31</sub>–C<sub>35</sub>) for bitumens from the Bazhenov Formation are essentially identical to those for the low-C<sub>29</sub>-sterane oil family. Modified from Peters et al (1994);{{citation needed}} courtesy AAPG.]]
Further support for a Bazhenov source is provided by the distribution of extended hopanes. As indicated in the figure below, the “Bazhenov” oils have extended hopane distributions virtually identical with the Bazhenov source rock extracts (indicated as bitumens in the figure). This positive correlation is strengthened because the homohopane distributions are somewhat unusual; thus, the similarity is unlikely to be fortuitous.
Further support for a Bazhenov source is provided by the distribution of extended hopanes. As indicated in the figure below, the “Bazhenov” oils have extended hopane distributions virtually identical with the Bazhenov source rock extracts (indicated as bitumens in the figure). This positive correlation is strengthened because the homohopane distributions are somewhat unusual; thus, the similarity is unlikely to be fortuitous.