Families of oils and source rocks in the central Mackenzie corridor: a geochemical oil-oil and oil-source rock correlation

Shimon Feinstein, Paul W Brooks, Martin G Fowler, Lloyd R Snowdon, G Keith Williams

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

The genetic history (i.e., source rock, generation, migration, and entrapment) of hydrocarbons has an important bearing on petroleum exploration. Biomarker distributions in four bitumen and oil samples and six samples of Cretaceous and Devonian potential source rocks, all from the central Mackenzie Corridor, were studied in an attempt to correlate them, classify the bitumens and oils and identify their source rocks. The techniques applied were Rock-Eval pyrolysis, liquid chromatographic fractionation, capillary gas chromatography, and gas chromatography-mass spectrometry.

On the basis of biomarker distributions, the samples may be classified into three oil/bitumen families and three source rock groups. The proportion of C27:C28:C29 regular steranes and presence of C30 4-desmethyl steranes, allow a clear distinction between the Cretaceous Slater River shales and the Devonian Canol and Bluefish shales. Likewise, the distribution of C27:C28:C29 steranes and the presence of C30 4-desmethyl steranes allows correlation of hydrocarbons (East Mackay B-45 oil and Russel M-07 bitumen) with a probable Cretaceous source, the Cretaceous Slater River shale.

The Norman Wells oil is characterized by relatively low Ts/Tm and diasterane/regular sterane ratios, both of which distinguish it from the bitumen extracted from the Bluefish A-49 well. These are also the main parameters used to differentiate the Devonian Canol and Bluefish shales. The Ts/Tm and the dia/regular sterane ratios prompted Snowdon et al. (1987) to suggest that the Canol, rather than the Bluefish, was probably the major source for the Norman Wells oil. The relatively high Ts/Tm and dia/regular sterane ratios in the bitumen from the Devonian Hume limestone in the Bluefish A-49 well indicate that it was generated mainly from the Bluefish Member of the Hare Indian Formation, rather than from the Canol Formation.

Rock-Eval parameters and polycyclic alkane isomerization ratios indicate that the majority of the potential source rocks examined range from immature to moderately mature, and that the related hydrocarbons have maturation levels similar to those of the source rocks. This lack of maturation contrast and the juxtaposition of the source and the reservoir rocks in each of the three hydrocarbon-source rock families identified suggest local hydrocarbon generation and accumulation with only limited migration.
Original languageEnglish
Title of host publicationSequences, Stratigraphy, Sedimentology: Surface and Subsurface — Memoir 15
EditorsD.P. James , D.A. Leckie
PublisherCanadian Society of Petroleum Geologists
Pages543-552
Volume15
StatePublished - 1988

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