Identification and geochemical significance of polarized macromolecular compounds in lacustrine and marine oils

Polarized macromolecular compounds in typical lacustrine and marine shale oils collected from the Ordos Basin and Tarim Basin of China were analyzed by FT-ICR-MS. Maturity was taken into consideration by diagenesis physical simulation experiments on shale oils, which had been collected at various temperature and pressure stages. The results showed that similar components existed in non-hydrocarbon and asphaltenes and the main peak compound classes of N₁ and O₂ were potential parameters for identifying typical marine oil and lacustrine oil in China. Nitrogen compounds/(nitrogen compounds and oxygen compounds), such as N₁/(O₂+N₁), N₁/(O₃+N₁), N₁/(N₁O₁+N₁O₂) are the maturity indicators, which are related with C-N and C-O bond energy. Differences in molecular components and weights between marine and lacustrine oils are the effective index to identify source maturity and sedimentary environment.