Abstract
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 (Ro) was established. The comparative analysis results showed that the MPDF and Ro 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.