鄂尔多斯北部直罗组中烃类包裹体地球化学特征及来源分析
- 中国科学院矿产资源研究重点实验室 北京 100029
- 收稿日期:
1900-01-01
- 修回日期:
1900-01-01
- 刊出日期:
2007-06-10
摘要: 对鄂尔多斯盆地东胜地区中侏罗统直罗组砂岩中烃类包裹体进行镜下观察、描述，利用压碎抽提法对烃类包裹体进行色谱—质谱分析，并与白垩系油苗、三叠系油砂及源岩抽提物进行对比，目的是探讨其来源。包裹体油生物标志物成熟度参数，C29ααα甾烷20S/(S+R)、C32αβ藿烷22S/(S+R)比值基本达到平衡值，利用甲基菲指数计算的镜质体反射率参数介于0.64%～0.82％之间，显示包裹体中石油烃已接近成熟—成熟热演化阶段；物质来源及沉积环境参数，ααα20R甾烷百分含量C27>C28<C29，C25/C26三环萜烷、规则甾烷/17αC29-33藿烷比值显示相对低值，结合伽马蜡烷指数、C35升藿烷指数等参数，综合反映了其来源应为弱氧化－还原环境下的腐殖—腐泥型湖相有机质。参数对比发现，包裹体油与三叠系油砂和三叠系源岩抽提物接近，而与白垩系油砂抽提物相差较远，说明砂岩中包裹体油主要来自三叠系湖相烃源岩。
Geochemical Characteristics and Source of Hydrocarbon Inclusions in Zhiluo Formation Sandstone in Dongsheng Area, Northern Ordos Basin
- Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029
- Received Date:
1900-01-01
- Rev Recd Date:
1900-01-01
- Publish Date:
2007-06-10
Abstract: First of all, the researchers observed and described hydrocarbon inclusions in Middle Jurassic Zhiluo Formation sandstones in Dongsheng area, northern Ordos basin under microscope and UV fluorescence, and then, carefully selected the sandstone samples containing hydrocarbon inclusions with high abundance. Subsequently, these samples were washed, crushed, extracted for hydrocarbons and analyzed for GC and GCMS and compared with oils extracted from Cretaceous sandstone, Triassic sandstone and source rock, respectively. The results show that C29 ααα sterane 20S/(20S+20R) and C32 αβ hopane 22S/(22S+22R) ratios of the inclusion oils are close to respective equilibrium values. Vitrinite reflectance values were calculated based on methylphenanthrene index(MPI) and have values from 0.64％ to 0.82％, suggesting that the inclusion oils are near mature to mature. Among C27, C28 and C29 ααα20R steranes, C27>C28<C29. C25/C26 tricyclic terpane and regular steranes/17αC29～33 hopanes ratios are relatively low. The values together with those of gammacerane index and homohopane index consistently indicate that the inclusion oils were derived from humicsapropel type organic matter under poor reducing freshwater to semisaline environment. The features are similar to those of organic matter extracted from Triassic sandstone and source rock, but are different from that of Cretaceous sandstone. Thus, it can be concluded that the inclusion oils were mainly derived from Triassic lacustrine facies source rock.
李宏涛. 鄂尔多斯北部直罗组中烃类包裹体地球化学特征及来源分析[J]. 沉积学报, 2007, 25(3): 467-473.
| 引用本文: |
李宏涛. 鄂尔多斯北部直罗组中烃类包裹体地球化学特征及来源分析[J]. 沉积学报, 2007, 25(3): 467-473.
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LI Hongtao. Geochemical Characteristics and Source of Hydrocarbon Inclusions in Zhiluo Formation Sandstone in Dongsheng Area, Northern Ordos Basin[J]. Acta Sedimentologica Sinica, 2007, 25(3): 467-473.
| Citation: |
LI Hongtao. Geochemical Characteristics and Source of Hydrocarbon Inclusions in Zhiluo Formation Sandstone in Dongsheng Area, Northern Ordos Basin[J]. Acta Sedimentologica Sinica, 2007, 25(3): 467-473.
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