关键词: 济阳坳陷, 盐湖沉积环境, 高硫稠油, 正构烷烃, 异构烷烃, 烃源岩, 可溶有机质, 低熟油

Abstract: The sulfur-rich heavy oil in Luojia-Kenxi area of Jiyang Depression can be classified as two kinds of sulfur-rich heavy oil and extra-heavy oil,according to their physical properties.The sulfur-rich heavy oil has the intact series of normal and isomeric alkanes,and the stereo-isomerization parameters of C₂₉ sterane are from 0.41 to 0.54,which are higher than those of general low-mature oil.The sulfur-rich heavy oil has the common characteristics of the low-mature oil in the salt lake depositional environment and contains high-abundance C₂₁ and C₂₂ pregnane,rare C₂₈-28,30-bisnorhopane,a series of methylhopane,hopane sulfide and sulfide seranes of C₁₆ and C₂₂.The normal and isomeric alkanes of the sulfur-rich extra-heavy oil were lost in some extent,but the characteristics of steranes,terpanes and most of aromatic hydrocarbons are similar to those of the primary heavy oil.The oil-to-source correlation and quantification of soluble organic matter from source rocks showed that the sulfur-rich heavy oil was mainly derived from the very good source rocks with the type-I and type-Ⅱ₁ kerogens in the hypersaline depositional environment of the E_s4 upper member of Shahejie Formation in Bonan Sag.The peak values of vitrinite reflectance for oil generation of good source rocks range from 0.55% to 0.60%.In the peak stage of vitrinite reflectance,the total soluble organic matter occupies 85% of the total organic matter in the source rocks.The sulfur-rich heavy oil was mainly generated from the soluble organic matter and showed the low-mature oil,which was not derived from the later thermal degradation of kerogen.

Key words: Jiyang Depression, salt lake depositional environment, sulfur-rich heavy oil, normal alkane, isomeric alkane hydrocarbon source rock, soluble organic matter, low-mature oil