Organic geochemistry characterization of the Yan 9 crude oils and oil-source rock correlations in Jingbian Oil Field, Ordos Basin

摘要

The geochemical characteristics of the Yan 9 reservoir were analyzed by means of the group composition and the biomarkers in order to clarify the oil source of the Yan 9 reservoir in Jingbian Oil Field. The results showed that the n-alkanes are distributed with a single mode with C-21 as the main carbon peak, C(30)hopane as the dominant biomarker, followed by C(29)hopane. Regular steroids are mainly C-29, while C-27 and C-28 are similar, showing an asymmetric V distribution. The Yan 9 crude oil has similar geochemical characteristics and unified material source and evolution degree. It is a mature crude oil derived from a source deposited in a weak oxidation-reduction environment under freshwater conditions. Oil-source correlation showed that the reservoir of Yan 9 mainly comes from the contribution of Chang 7 hydrocarbon source rock in Jingbian Oil Field.