Application of factor analysis to investigating molecular geochemical characteristics of organic matter and oil sources: An exploratory study of the Yanchang Formation in the Ordos Basin, China.

Due to the similarity of the biomarker characteristics of the source rocks of different layers, the progress of the oil source research of the Yanchang Formation in the Ordos Basin is difficult and slow, which highlights the shortcomings of traditional research methods. Given this, this paper uses the gas chromatography-mass spectrometry analysis results of a large volume of samples of the Yanchang Formation in the basin as the dataset, and performs an exploratory application of the factor analysis (FA, a multivariate statistical method) to analyze the molecular geochemical characteristics of organic matter, with an aim to find features that have not been noticed in the past, and give a reasonable explanation for the oil source. The findings are summarized as below: with the help of multivariate (31 molecular geochemical parameters are introduced), FA can quantify many geochemical properties of samples well, which brings convenience to research. Based on the results, it was found that parameters such as C 26 TT/C 25 TT, sterane/hopane, and ΣC 19-26 TT/C 30 αβ can effectively distinguish the samples of different areas and layers, and it is further believed that the Chang 9 source rock has higher contributions to adjacent layers (mainly the Chang 8–Chang 10 oil groups) in areas where it is abundant (mainly the Wuqi-Zhidan area), while in the other areas and layers, oil is mostly attributed to the Chang 7 source rock. •Conventional oil-source research methods are inadequate when facing the Yanchang Fm. of Ordos Basin. •Exploratively combine factor analysis methods to analyze a large amount of GC-MS data. •Factor analysis effectively reveals differences in petroleum geochemistry among different source rocks. • This research has the potential value of promoting the development of petroleum geochemistry technology. [ABSTRACT FROM AUTHOR]