石油与天然气地质 ›› 2006, Vol. 27 ›› Issue (2): 218-224.doi: 10.11743/ogg20060212

• 成藏(矿)作用 • 上一篇    下一篇

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及油源对比

郭艳琴, 李文厚, 陈全红, 曹红霞, 张道锋   

  1. 西北大学, 地质学系, 大陆动力学国家重点实验室, 陕西, 西安, 710069
  • 收稿日期:2006-01-17 出版日期:2006-04-25 发布日期:2012-01-16
  • 基金资助:

    国家重点基础研究发展计划(973)项目(2003CB214602);长江学者和创新团队发展计划资助项目(IRT0559)

Geochemical behaviors of oil and oil-source correlation in Yanchang Yan'an Formations in Ansai-Fuxian area,Ordos basin

Guo Yanqin, Li Wenhou, Chen Quanhong, Cao Hongxia, Zhang Daofeng   

  1. Department of Geology, Northwest University, Xi'an, Shaanxi, 710069
  • Received:2006-01-17 Online:2006-04-25 Published:2012-01-16

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。

关键词: 碳同位素, 饱和烃气相色谱, 生物标志物, 油源对比, 安塞-富县地区, 鄂尔多斯盆地

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.

Key words: carbon isotope, gas chromatogram of saturated hydrocarbon, biomarker, oil-source correlation, Ansai-Fuxian area, Ordos basin

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