Cretaceous oil-source correlation in Guaizihu Sag, Yin'gen-E'ji'naqi Basin

Recently, high oil product was gained in the second member of the Cretaceous Bayingebi Formation (K₁b₂) in the well X in the Guaizihu Sag of Yin'gen-E'ji'naqi Basin, which revealed a bright exploration prospect. It has not obtained a quite unified understanding of petroleum source, so some research were made on the oil-source correlation,which will be helpful for the prediction of hydrocarbon reservoir and the selection of exploration direction. The analyses of composition, biomarker and carbon isotope were made with oil sand samples from the first member of Suhongtu Formation (K₁s₁), crude oil samples from the second member of Bayingebi Formation, and mudstone samples from the second member of Suhongtu Formation (K₁s₂) as well as and the second and first members of Bayingebi Formation. The geochemical features of oil sands, crude oil are close with K₁b₁ source rocks, showing high contents of C₃₀-diahopane and gammacerane, low Pr/Ph and high maturity. The good similarity reflects that K₁s₁ oil sands and K₁b₂oil are homologous, and their parent material are both from K₁b₁source rocks.