Geochemical Characteristics and Organic Matter Provenance of Shale in the Jurassic Da’anzhai Member, Northeastern Sichuan Basin

Rock pyrolysis, organic petrology, vitrinite reflectance, gas chromatography-mass spectrometry (GC-MS) analysis, and biomarker compound analysis were performed to comprehensively analyze the geochemical characteristics of Jurassic Da’anzhai Member (J 1 da) shale strata in Yuanba Puguang areas northeastern Sichuan Basin. Then matter provenance sedimentary environment further analyzed. Finally, significance oil exploration J da was discussed. Results show that second section 2 ) has relatively high abundance (1.24% TOC ), type Ⅱ-dominated type, which is most favorable wells Y1 T1 study area. The maturity hydrocarbon phases are quite different, 1.01% R o dominated by generation area, while it 1.67% Content chromatograms biomarkers including n-alkanes, tricyclic terpanes, C 24 tetracyclic 27 -C 28 29 regular steranes matters derive from both terrestrial higher plants lower aquatic organisms, with slightly differentiated mixed ratio each sublayer. Characteristics Pr/Ph, γ-cerane hopanes compounds indicate overall depositional a freshwater lacustrine environment, saline lake deposits local intervals rapid changes have resulted obvious stratification water body, frequent interbeds, strong heterogeneity strata. Comprehensive shows shale/mud microfacies semi-deep subfacies interbedded siltstone shell bank shallow facies for enrichment. Deeper burial depth make enrichment gas/oil (GOR); moreover, thicker organic-rich targets evaluation.