A mineral analysis method for shale based on SEM and X-ray EDS

doi:10.3969/j.issn.1672-7703.2017.06.004

Abstract

Abstract: A shale gas system is mainly composed of clay mineral-rich shale and its remarkable characteristic is self-generating and selfpreserving. When the high-resolution scanning electron microscope (SEM) is used to analyze the micro pore structures and mineral compositions of shale, the surface of the samples shall be polished by means of argon ion to meet the requirements of sample preparation. The argon ion polishing can improve the quality of SEM images, but in the meantime, it deteriorates the authigenic forms of the minerals, increasing the difficulty of SEM mineral identification. In order to identify and analyze the mineral compositions of shale more intuitively, the SEM images and EDS (energy dispersive spectrum) characteristics of main minerals in the polished shale samples were summarized based on the analysis results of FIB-SEM (focused ion beam-scanning electron microscope) and X-ray EDS. Then, the corresponding chart was established. And by virtue of this chart, the mineral compositions of shale can be analyzed qualitatively and quantitatively. It is shown that the qualitative identification results are consistent with the EDS scanning results. The error between the mineral compositions calculated by means of the software after the mineral division and extraction and the X-ray diffraction experiment results is larger. And it is recommended to optimize the quantitative mineral calculation method based on image analysis.

Key words: shale gas, mineral analysis, SEM, EDS, argon ion polishing

CLC Number:

TE125

Zhou Shangwen, Xue Huaqing, Guo Wei. A mineral analysis method for shale based on SEM and X-ray EDS[J]. China Petroleum Exploration, 2017, 22(6): 27-33.

References

[1] Curtis J B. Fractured Shale-gas Systems[J]. AAPG Bulletin, 2002,86(11):1921-1938.
[2] Jarvie D M, Ronald J H, Tim E R, Richard M P. Unconventional shale gas systems:The Mississippian Barnett shale of North-central Texas as one model for thermogenic shale-gas assessment[J]. AAPG Bulletin, 2007,91(4):475-499.
[3] Ross D J K, Bustin R M. Shale gas potential of the Lower Jurassic Gordondale Member, Northeastern British Columbia, Canada[J]. Bulletin of Canadian Petroleum Geology, 2007,55(1):51-75.
[4] 冯建辉,牟泽辉. 涪陵焦石坝五峰组-龙马溪组页岩气富集主控因素分析[J]. 中国石油勘探,2017,22(3):32-39. Feng Jianhui, Mou Zehui. Main factors controlling the enrichment of shale gas in Wufeng Formation-Longmaxi Formation in Jiaoshiba area, Fuling shale gas field[J]. China Petroleum Exploration, 2017,22(3):32-39.
[5] Bustin R M, Bustin A, Ross D J K, Cui X. Shale gas opportunities and challenges[J]. Search and Discovery Articles, 2009,40382:20-23.
[6] 郭旭升,胡东风,魏志红,李宇平,魏祥峰. 涪陵页岩气田的发现与勘探认识[J]. 中国石油勘探,2016,21(3):24-37. Guo Xusheng, Hu Dongfeng, Wei Zhihong, Li Yuping, Wei Xiangfeng. Discovery and exploration of Fuling shale gas field[J]. China Petroleum Exploration, 2016,21(3):24-37.
[7] Loucks R G, Reed R M, Ruppel S C, Jarvie D M. Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale[J]. Journal of Sedimentary Research, 2009,79(12):848-861.
[8] 尉鹏飞,张金川,隆帅,彭建龙,邓恩德,吕艳南,等. 四川盆地及周缘地区龙马溪组页岩微观孔隙结构及其发育主控因素[J]. 中国石油勘探,2016,21(5):42-51. Wei Pengfei, Zhang Jinchuan, Long Shuai, Peng Jianlong, Deng Ende, Lü Yannan, et al. Characteristics and controlling factors of microscopic pore structure of Longmaxi Formation in Sichuan Basin and its periphery[J]. China Petroleum Exploration, 2016,21(5):42-51.
[9] 陈尚斌,朱炎铭,王红岩,刘洪林,魏伟,方俊华. 四川盆地南缘下志留统龙马溪组页岩气储层矿物成分特征及意义[J]. 石油学报, 2011,32(5):775-782. Chen Shangbin, Zhu Yanming, Wang Hongyan, Liu Honglin, Wei Wei, Fang Junhua. Characteristics and significance of mineral compositions of Lower Silurian Longmaxi Formation shale gas reservoir in the Southern Margin of Sichuan Basin[J]. Acta Petrolei Sinica, 2011,32(5):775-782.
[10] 伍岳,樊太亮,蒋恕,李一凡,张俊鹏,丁怀宇. 四川盆地南缘上奥陶统五峰组-下志留统龙马溪组页岩矿物组成与脆性特征[J]. 油气地质与采收率,2015,22(4):59-63. Wu Yue, Fan Tailiang, Jiang Shu, Li Yifan, Zhang Junpeng, Ding Huaiyu. Mineralogy and brittleness features of the shale in the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation in Southern Sichuan Basin[J]. Petroleum Geology and Recovery Efficiency, 2015,22(4):59-63.
[11] 刘友祥,俞凌杰,张庆珍,鲍芳,卢龙飞. 川东南龙马溪组页岩的矿物组成与微观储集特征研究[J]. 石油实验地质,2015,37(3):328-333. Liu Youxiang, Yu Lingjie, Zhang Qingzhen, Bao Fang, Lu Longfei. Mineral composition and microscopic reservoir features of Longmaxi shales in South Eastern Sichuan Basin[J]. Petroleum Geology & Experiment, 2015,37(3):328-333.
[12] 张明扬,李贤庆,董泽亮,郭曼,孙萌萌,樊剑平. 皖南地区下寒武统荷塘组页岩矿物组成及脆度分析[J]. 矿物岩石地球化学通报, 2015,34(1):177-183. Zhang Mingyang, Li Xianqing, Dong Zeliang, Guo Man, Sun Mengmeng, Fan Jianping. Analyses on mineral compositions and brittleness of the Lower Cambrian Hetang Formation shale in South Anhui province[J]. Bulletin of Mineralogy, Petrology and Geochemistry, 2015,34(1):177-183.
[13] 原园, 姜振学, 喻宸, 郭天旭, 申玉山, 赵若彤. 柴北缘中侏罗统湖相泥页岩储层矿物组成与脆性特征[J]. 高校地质学报, 2015,21(1):117-123. Yuan Yuan, Jiang Zhenxue, Yu Chen, Guo Tianxu, Shen Yushan, Zhao Ruotong. Mineral compositions and brittleness of the Middle Jurassic lacustrine shale reservoir in Northern Qaidam Basin[J]. Geological Journal of China Universities, 2015,21(1):117-123.
[14] Wu Y, Fan T, Zhang J, Jiang S, Li Y, Zhang J. Characterization of the Upper Ordovician and Lower Silurian marine shale in North Western Guizhou province of the Upper Yangtze Block, South China:implication for shale gas potential[J]. Energy & Fuels, 2014,28(6):3679-3687.
[15] Zhou S, Yan G, Xue H, Guo W, Li X. 2D and 3D nanopore characterization of gas shale in Longmaxi Formation based on FIB-SEM[J]. Marine and Petroleum Geology, 2016,73:174-180.
[16] 王羽,金婵,汪丽华,王建强,姜政,王彦飞,等. 应用氩离子抛光-扫描电镜方法研究四川九老洞组页岩微观孔隙特征[J].岩矿测试, 2015,34(3):278-285. Wang Yu, Jin Chan,Wang Lihua, Wang Jianqiang, Jiang Zheng, Wang Yanfei, et al. Characterization of pore structures of Jiulaodong Formation shale in the Sichuan Basin by SEM with Ar-ion milling[J]. Rock and Mineral Analysis, 2015,34(3):278-285.
[17] 刘伟新,史志华,朱樱,曹寅. 扫描电镜/能谱分析在油气勘探开发中的应用[J]. 石油实验地质,2001,23(3):341-343. Liu Weixin, Shi Zhihua, Zhu Ying, Cao Yin. Application of SEM/EDX analysis in petroleum exploration and production[J]. Petroleum Geology & Experiment, 2001,23(3):341-343.
[18] 于建勇,于冰. 粘土矿物EDAX能谱仪定量分析方法研究[J]. 电子显微学报,2006,25(增刊1):312-313. Yu Jianyong, Yu Bing. Research of quantitative analysis method of clay mineral based on EDAX[J]. Journal of China Electronic Microscopy Society, 2006,25(Supp.1):312-313.
[19] 黄锐,张新华,秦黎明. 基于元素含量的页岩矿物成分及脆性评价方法[J]. 中国石油勘探,2014,19(2):85-90. Huang Rui, Zhang Xinhua, Qin Liming. Method of evaluation of shale mineral components and brittleness on basis of element content[J]. China Petroleum Exploration, 2014,19(2):85-90.
[20] 宋土顺,李轩,张颖,王成,刘立,刘娜,等. QEMSCAN矿物定量分析技术在成岩作用研究中的运用:以扶余油层致密砂岩为例[J]. 地质科技情报,2016,35(3):193-198. Song Tushun, Li Xuan, Zhang Ying, Wang Cheng, Liu Li, Liu Na, et al. QEMSCAN mineral quantitative analysis of tight sandstone diagenesis in Fuyu oil layer, Daqing Placanticline[J]. Geological Science and Technology Information, 2016,35(3):193-198.
[21] 王坤阳,杜谷,杨玉杰,董世涛,喻晓林,郭建威. 应用扫描电镜与X射线能谱仪研究黔北黑色页岩储层孔隙及矿物特征[J]. 岩矿测试, 2014,33(5):634-638. Wang Kunyang, Du Gu, Yang Yujie, Dong Shitao, Yu Xiaolin, Guo Jianwei. Characteristics study of reservoirs pores and mineral compositions for black shale, Northern Guizhou, by using SEM and X-ray EDS[J]. Rock and Mineral Analysis, 2014,33(5):634-638.
[22] 王秀平,牟传龙,葛详英,陈小炜,周恳恳,王启宇,等. 川南及邻区龙马溪组黑色岩系矿物组份特征及评价[J]. 石油学报,2015, 36(2):150-162. Wang Xiuping, Mou Chuanlong, Ge Xiangying, Chen Xiaowei, Zhou Kenken, Wang Qiyu, et al. Mineral component characteristics and evaluation of black rock series of Longmaxi Formation in southern Sichuan and its periphery[J].Acta Petrolei Sinica, 2015,36(2):150-162.