东营凹陷北带深层Es下4盐下段轻质油地球化学特征及油源探讨

根据饱和烃、轻烃、双金刚烷的分析资料，全面剖析了东营凹陷北带E_s^下₄盐下段轻质油的地球化学特征。研究发现，轻质油Pr/Ph值为0.7，略呈植烷优势，轻烃中以正烷烃占优势，异构烷烃相对较少，2-甲基己烷/3\|甲基己烷的比值大于1，表征油源岩为还原的湖相沉积，生源母质较好。经轻烃指纹对比，结合双金刚烷成熟度指标分析认为，轻质油来自于E_s^下₄盐下段烃源岩。进一步表明东营凹陷深层E_s^下₄盐下段将成为勘探重要的潜力区带。

Geochemical Characteristics and Source of Light Oil in the Deep Eslower4 Layers Underlying Salt in the Northern Dongying Sag

Based on the analysis of saturated hydrocarbons, light hydrocarbons and double diamantane, the geochemical characteristics of the light oil in the Es^lower₄ (the lower part Es^lower₄  Member) layers underlying salt were systematically studied in the northern Dongying Sag. It is discovered that the phytane is slightly predominant with the Pr/Ph ratio 0.7 in the light oil. n-alkanes are predominant and isoalkanes are less in light hydrocarbons. The 2\|methylhexane/3\|methylhexane ratio is larger than 1. These indicate that the source rocks were in a reducing lacustrine depositional environment and the parent material is preferable. The light hydrocarbon fingerprint correlation and the double diamantine maturity index analysis show that the light oil originated from theEs^lower₄ source rocks underlying salt. Therefore, theEs^lower₄  layers underlying salt are important prospects for exploration in the Dongying Sag.