济阳坳陷下第三系湖相生油岩的微观特征  

Micro-characteristics of Paleogene Lacustrine Petroleum Source Rocks in Jiyang Depression

作　　者：刘传联[1] 舒小辛[1] 刘志伟[1] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092

出　　处：《沉积学报》2001年第2期293-298,共6页Acta Sedimentologica Sinica

摘　　要：利用背散射电子成像技术、扫描电镜和能谱分析对山东济阳坳陷下第三系主要湖相生油岩的微观组构、成分特征进行了高分辨率的观察和分析 ,同时对其中藻类化石丰度进行了定量统计。结果显示 ,这些生油岩既有共性又有显著的差异。共性表现在它们都具有纹层状构造 ,而且有机质都特别丰富 ,呈纹层分布。差异性表现在纹层单元的成分明显不同 :富有机质纹层页岩由有机质纹层和粘土矿物纹层组成 ;钙质纹层页岩则有两种情况 :一类由有机质纹层和钙质超微化石纹层组成 ,另一类由有机质纹层和粗粒方解石纹层组成 ,粗粒方解石中含有钙质超微化石 ;钙质纹层泥岩由细粒方解石纹层和含有机质的粘土矿物纹层组成。生油岩中有机质的分布也有两种形式 :一类是有机质纹层 ,另一类则是藻类化石层 ,如沟鞭藻化石层和钙质超微化石 (颗石藻 )The Jiyang depression is one of the subbasins of the Bohai Gulf Rift Basin in the eastern China. About 65 oil fields have been discovered in this depression over the past 30 years and the oil mainly derived from three types of finely laminated lacustrine rocks of Shahejie Formation( Eocene-Oligocene).These source rocks are organic rich laminated shale, calcareous laminated shale and calcareous laminated mudstone.High resolution studies have been carried out on these petroleum source rocks by scanning electron microscope(SEM), backscattered electron imagery(BSEI) and energy dispersive spectrometry(EDS). The results show that these source rocks are all laminated sedimentary rocks, and organic matters are very abundant in it, but they have the different sediment composition. Organic rich laminated shale is composed of organic matter lamination and clay mineral lamination; The clay rich laminae range in thickness from 15 to 100μm and are predominantly composed of illite(80%). In addition, they have subsidiary components which comprise ankerite(5～10%), pyrite(1～3%),quartz(1～2%) and feldspar(1%～2%) along with trace amounts of apatite(0.03%). In contrast, the organic rich laminae are thinner than the clay rich laminae, ranging from 6～50 μm and are predominantly composed of amorphous organic matter(20%～70%),as well as organic matter, these laminae also contain detrital clay (predominantly illite), silt sized quartz, feldspar(1%～2%),and pyrite(1%～3%). Displacive calcite layers were also present. The calcite in these layers consits of low Mg, non ferroan calcite.In addition to the characteristic 'beef' texture of this calcite, these layers also contain pyrite framboids,detrital quartz and ankerite. Calcareous laminated shale is composed of organic matter lamination and coccolith or coarse calcite lamination; The coccolith laminae laminae is composed almost wholly of one species, Reticulofenestra bohaiensis and the coarse grained calcite lamine are composed of coarse calcite(10～20 μm) and a

关 键 词：微观特征 生油岩 下第三系 济阳坳陷 前散射电子成像技术 扫描电镜 能谱分析 

分 类 号：P618.130.1[天文地球—矿床学] TE12[天文地球—地质学]