渝东南地区古生代富有机质页岩超显微有机岩石学特征研究

发布时间：2018-03-05 08:03

本文选题：牛蹄塘组　切入点：龙马溪组　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：自美国页岩气进行商业化开采以来,以页岩气为主的新能源勘探正在受到各个国家不同程度的重视。页岩即是烃源岩,又是储层,油气地质工作者对这种富有机质页岩形成的地质理论进行了广泛的讨论。近几年,一些学者利用扫描电镜、能谱仪分析、氮气吸附等一系列先进的测试技术并结合有机地球化学参数,将这种富有机质页岩的微观特征与有机地化特征结合起来进行研究,取得了丰硕的成果。但目前对富有机质页岩中硅的来源、微观孔隙特征及其与有机岩石学方面的研究尚薄弱,一些参数之间的相关性尚不明确。本文重点探讨了硅质页岩中硅的来源,研究了孔隙结构特征及其与有机地化参数之间的关系。文中以渝东南地区下寒武统牛蹄塘组和下志留统龙马溪组两套富有机质页岩为研究对象,通过文献调研、样品的采集、相关实验测试及结果讨论,对富有机质页岩中硅的成因及其孔隙特征等方面取得了以下主要认识:(1)两套富有机质页岩中孔隙类型丰富、孔隙结构多样。孔隙类型主要以介孔为主,微孔、宏孔次之。孔隙连通性整体较差;微观孔隙的孔容体积主要以介孔贡献为主。两套富有机质页岩微孔孔容与比表面积具有很好的相关性;介孔孔容与比表面积相关性不强;宏孔孔容与比表面积具负相关性。(2)有机碳含量(TOC)对不同大小孔隙的孔容发育和比表面积具有不同的控制作用。对于微孔,TOC在一定范围之内,两者呈正相关性,当TOC含量超过临界值,比表面积表现为低值;TOC对介孔孔容几乎不具相关性,对宏孔孔容的发育具有微弱正相关性。(3)高TOC与生物化石丰富程度密切相关。下寒武统牛蹄塘组和下志留统龙马溪组两套页岩有机碳含量(TOC)高,TOC一般分布在0.77%-14.47%,平均值达6.38%。普通薄片与电子扫描电镜显示,这两套富有机质页岩中含有大量藻类、笔石等生物化石。生物的发育、繁殖,对页岩中TOC的贡献较大。(4)对富有机质页岩中硅的来源进行了研究。两套富有机质页岩中富含C、Si、O、Al等元素,元素分析实验表明,硅主要源于生物成因。电子扫描电镜中发现富有机质页岩中存在大量含硅的生物化石也进一步验证了硅的生物成因。
[Abstract]:Since the commercial exploitation of shale gas in the United States, new energy exploration, which is dominated by shale gas, has been paid more and more attention to by various countries. Shale is both a source rock and a reservoir. The geological theory of the formation of organic shale has been extensively discussed by oil and gas geologists. In recent years, some scholars have used scanning electron microscopy (SEM) and energy spectrometer (EDS) to analyze the formation of organic shale. A series of advanced measurement techniques, such as nitrogen adsorption, combined with organic geochemical parameters, combined the microcosmic and organic geochemical characteristics of the organic shale. However, the source of silicon in organic shale, micropore characteristics and its relationship with organic petrology are still weak. The correlation between some parameters is not clear. This paper focuses on the source of silicon in siliceous shale. The relationship between pore structure and organic geochemical parameters was studied. Two sets of organic shale rich in organic matter shale of the Lower Cambrian Niutetang formation and Lower Silurian Longmaxi formation were studied in this paper. The related experimental tests and the results of the discussion show that the formation and pore characteristics of silicon in organic shale are mainly known as follows: (1) two sets of organic shale are rich in pore types. The pore structure is diverse. The main pore types are mesoporous, micropore, macro pore, and the overall porosity connectivity is poor. The volume of micropore volume is mainly mesoporous. Two sets of organic shale micropore volume have good correlation with specific surface area, but the correlation between mesoporous volume and specific surface area is not strong. There is a negative correlation between macro pore volume and specific surface area. TOC) has different control effects on pore volume development and specific surface area of different pore sizes. For micropore TOC, there is a positive correlation between them. When the content of TOC exceeds the critical value, the specific surface area of TOC shows little correlation with mesoporous volume. The high TOC is closely related to the abundance of fossils. Two sets of shale organic carbon content (TOC) of the Lower Cambrian Niutetang formation and Lower Silurian Longmaxi formation are generally distributed in the range of 0.77 to 14.47, with an average of 0.77 to 14.47. A value of 6.38. Ordinary sheets and electron scanning electron microscopy show, These two sets of organic shale contain a great deal of algae, graptolite and other biological fossils. The source of silicon in organic shale is studied. Two sets of organic shale are rich in elements such as C _ 2O _ O _ 2O _ (Al). The existence of a large number of silicon-rich biofossils in organic shale is further verified by electron scanning electron microscopy (SEM).
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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