| Abstract:The surface outcrops of Jurassic marine strata in the Shenglihe area of the Qiangtang Basin show a large amount of petroleum. Previous research indicates the presence of multiple petroleum systems characterized by complex properties. On the basis of previous research work, the main research object of this study is the petroleum display of the central oil shale outcrop, exploration well core and surface oil and gas display of the middle Jurassic Buqu Formation (J2b). Through TOC analysis, rock pyrolysis, saturated hydrocarbon chromatography and saturated hydrocarbon chromatography-mass spectrometry analysis, the source rock types and oil sources in Shengli River area are studied in detail, which provides more theoretical basis for further petroleum exploration in this area. The results show that the organic matter within the J2b middle stratum is primarily Type II, which has a high potential for oil generation. The oil predominantly originates from reduced marine sedimentary environments. The organic matter input of the samples in the study area was mainly lower aquatic organisms, DB4142 was mixed with lower aquatic organisms and higher plants, and BD4902 was mainly higher plants. The oil has reached maturity, as evidenced by the presence of 25-norholane series compounds in all samples, suggesting a history of significant biodegradation. Utilizing cluster analysis based on fingerprint and biomarker parameter characteristics, we classified the oil into four categories: A, B, C, and D. Among them, Class A oil mainly comes from the source rocks of the same horizon (J2b), while Classes B, C, and D exhibit little to no contribution from the J2b source rocks, and may come from other horizon source rocks. |
