石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (2): 175-181，228.doi: 10.11743/ogg20110203

• 石油与天然气地质 • 上一篇    下一篇

东濮凹陷文明寨地区三叠系低熟油特征及成藏模式

  

  • 出版日期:2011-04-28 发布日期:2011-09-26

Characteristics and poolforming patterns of the Triassic immature oil in Wenmingzhai area, the Dongpu Depression

  • Online:2011-04-28 Published:2011-09-26

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被引次数

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摘要：

摘要：应用地球化学研究方法，对东濮凹陷北部文明寨地区三叠系原油、油砂抽提物及濮卫地区沙河街组三段下亚段烃源岩进行了族组成、碳同位素、饱和烃色谱-质谱等实验分析。结果表明,文明寨地区三叠系原油与含油砂岩抽提物的饱和烃含量在39.44%~51.01%，族组分碳同位素分布在-28.92‰~-26.54‰（PDB），芳烃、非烃和沥青质组分之间的同位素分馏效应较小；Pr/Ph值小于0.5，具有明显的植烷优势；甾烷C2920R/(20R+20S)值为0.29~0.34， C29αββ/(ααα+αββ)值为0.25~0.34，甾烷系列中C27含量略占优势，重排甾烷含量极低；γ-蜡烷含量较高，γ-蜡烷/C30藿烷值在0.70~0.81，反映了高盐度水体沉积环境下形成的低熟油特征。油源对比分析认为，文明寨地区三叠系低熟油的烃源灶为具有盐岩沉积建造的濮卫地区沙河街组三段—四段泥岩，其成藏模式为新生古储型油气藏。

关键词: 关键词：生物标志化合物, 成藏模式, 低熟油, 三叠系, 东濮凹陷

Abstract:

Abstract: Experimental analyses of group composition, carbon isotope and saturated hydrocarbon chromatogrammass spectrum were carried out on the crude oil and oil sand extract samples from the Triassic in Wenmingzhai area and the source rocks in the lower 3rd member of Shahejie Formation in Puwei area, Dongpu depression. The saturated hydrocarbon content of the crude oil and oil sand extract is in the range from 39.44% to 51.01%. Their carbon isotope of group composition ranges from-28.92‰ to-26.54‰ (PDB), and the fractionation effect of the carbon isotope among aromatic hydrocarbon, nonhydrocarbon and asphaltenes is relatively insignificant. The Pr/Ph ratio is less than 0.5, indicating the predominance of Phytane. The values of sterane C29 20R/(20R+20S) and C29 αββ / (ααα+αββ) are 0.29-0.34 and 0.25-0.34 respectively. The C27content is slightly predominant in the sterane’s series, while the diasteranes content is extremely low. The gammacerance content is relatively high and the gammacerance to C30 hopanes ratio is 0.70-0.81, indicating the geochemical characteristics of immature oil formed in a sedimentary environment with high water salinity. Oilsource correlation reveals that the immature oil in the Triassic reservoirs in Wenmingzhai area are sourced from the mudstone in the 3rd and 4th members of Shahejie Formation in Puwei area. The poolforming pattern is that hydrocarbons generated by young source rocks accumulate in old reservoirs.