Integrating Biomarker Analysis with Carbon Stable Isotope Signaturesfor Genetic Classification and Tracing Possible Migration Pathways ofHydrocarbons of Pre Caspian Basin

摘要

This paper presents the results of gas chromatography-mass spectrometry studies(GCMS-SIM)of 170oil samples derived from 32 different fields,located in the southern parts of the Pr-Caspian basin forthe genetic classification of oils based on their biomarker and aromatic compositions.In addition,10representative oil samples from different fields were chosen for carbon isotope analysis of oils,theirfractions and individual n-alkanes.The genetic classification based on biomarker distributions revealeddifferent types of oils,distinguishable mainly by lithology of their source rocks:according to their terpanedistributions oil samples from Aktube,Dosmukhambetov,S.Nurzhanov,Karasor,Teren-uzek,Akniyaz,Western Prorva and Kisymbai fields were generated in carbonate source rocks,while samples from the restfields were derived from shaly source rocks.Oils of Karashiganak and Balgimbayev also have a certaincontribution of carbonate OM.The results of PCA cluster analysis based on biomarker distributions indicatethe presence of genetically different oils in the studied fields.Also it was attempted to determine the directionof hydrocarbon migration pathways between certain objects and horizons.