【摘要】 原油族组成、碳同位素、饱和烃气相色谱及萜烷、甾烷等生物标志化合物特征分析显示,鄂尔多斯盆地安塞-富县地区延长组-延安组原油地球化学特征相近,为低成熟-成熟原油。原油饱和烃含量在70%以上;碳同位素值偏轻,δ13C值一般小于-31‰;正构烷烃分布完整,呈单峰型,主峰碳为C17—C23。原油生物标志物特征是,五环萜烷含量高于三环萜烷,以C30-藿烷、C29-降藿烷为主,伽马蜡烷含量少;甾烷以C27-胆甾烷、C28-麦角甾烷及C29-谷甾烷为主,规则甾烷呈不对称“V”字型分布,C28-甾烷含量较低,C27-甾烷与C29-甾烷含量相近。原油和源岩的地球化学特征分析对比表明,长8—长4+5半深湖-深湖相腐泥-混合型泥岩是主要烃源岩。生物标志物特征显示原油具有一定的运移效应。更多还原

【Abstract】 Crude oil analyses,such as group compositions,carbon isotopes and gas chromatograms of saturated hydrocarbon,as well as characteristics of terpane,sterane and other biomarkers,indicate that crude oil in Yanchang-Yan’an Formations in Ansai-Fuxian area have similar geochemical behaviors and are of low-mature-mature oil.The content of saturated hydrocarbon is over 70%,and the carbon isotope value is relatively light with δ¹³C commonly lower than-31‰.The distribution of normal alkane is complete and appears as single-peak type,with the main peak carbons to be C₁₇-C₂₃.The biomarkers of the oil are characterized by the followings: the content of pentacyclic terpane is larger than that of tricyclic terpane,with C₃₀ hopane and C₂₉ norhopane as the dominant components,and gammacerane as the minor component;sterane is dominated by C₂₇ cholestane and C₂₈ ergostane and C₂₉ sitostane;the homosteranes appear to be in asymmetrical "V" distribution,with relatively low C₂₈ sterane content and about the same C₂₇ and C₂₉ sterane contents.Analyses of geochemical beha-（viors） and correlation of oil and source rocks show that the semideep-deep lake facies sapropelic-mixed type mudstones that occur between Chang 8 and Chang 4+5 reservoirs are the main source rocks.The characteristics of biomarkers reveal that the oil has a certain migration effects.更多还原