Geochemistry of Aromatic Fractions in Es4 Oil Extracts from the South Slope of Dongying Sag and Its Implications

In view of the characteristics of oils from different production areas in the South Slope of Dongying Sag, detailed geochemical analysis of aromatic hydrocarbon in Es4 extracts were conducted. The results show that some typical high plants -sourced compounds are widely spread, such as pyrene, benzopyrene, fluoranthene, chryaene, benzofluoranthrene, perylene and cadalene. The ratios of 1,2,5-/1,3,6-TMN are 0.39∼1.04, 9-MP isomeride is in high content of 7.02-12.53%, and about 0.05%∼14.50% of retene is detected, suggesting the Es4 extracts are typical terrestrial origin. In F-DBF-DBT series, dibenzothiophene(DBT) is dominated with content of 33.07-73.17%, while dibenzofurane(DBF) is 9.56-33.20%, showing a reduction condition of brackish-saline lake. Furthermore three types of depositional environment can be distinguished according to the reduction intensities. The RICs are characterized by double peak with tricyclic aromatic compounds in predominance, ratios of 2,3,6-/(2,3,6 + 1,2,5)-TMN are 0.37-0.64, MPI1 and MPI2 are 0.21-0.61 and 0.24-0.72 respectively, corresponding to the maturity of 0.53-0.77%Rc, indicating a mature stage.