Relationship between methylphenanthrene distribution and organic matter maturity: a case study of Yangchang Formation Chang 7 source rocks, Erdos Basin, China

摘要

The methylphenanthrene component of Chang 7 source rocks in the Ordos Basin was analyzed using gas chromatograph-mass method. The relationship between methylphenanthrene index (MPI), methylphenanthrene distribution fraction (MPDF) and vitrinite reflectance (R-o) was established. The comparative analysis results showed that the MPDF and R-o were positively correlated and the correlation coefficient was high. Therefore, it was more accurate that the Chang 7 source rocks were determined by MPDF. Based on the established relational expression, the maturity of Chang 7 lacustrine source rocks in the Ordos Basin was calculated. The obtained results were consistent with actual geological background.