石油学报 ›› 2020, Vol. 41 ›› Issue (1): 27-42.DOI: 10.7623/syxb202001003

• 地质勘探 • 上一篇    下一篇

鄂西黄陵背斜南翼下寒武统水井沱组页岩孔隙结构与吸附能力

何晶1, 何生1, 刘早学2, 翟刚毅3, 王亿2, 韩元佳1, 万阔1, 魏思乐1   

  1. 1. 中国地质大学(武汉)构造与油气资源教育部重点实验室 湖北武汉 430074;
    2. 湖北省地质调查院 湖北武汉 430030;
    3. 中国地质调查局油气资源调查中心 北京 100029
  • 收稿日期:2019-05-24 修回日期:2019-11-22 出版日期:2020-01-25 发布日期:2020-02-06
  • 通讯作者: 何生,男,1956年1月生,1982年获武汉地质学院学士学位,2002年获Curtin University of Technology博士学位,现为中国地质大学(武汉)教授、博士生导师,主要从事油气地质教学和科研工作。Email:shenghe@cug.edu.cn
  • 作者简介:何晶,女,1995年10月生,2017年获长江大学学士学位,现为中国地质大学(武汉)资源学院矿产普查与勘探专业硕士研究生,主要从事页岩气地质研究。Email:2562757891@qq.com
  • 基金资助:

    国家自然科学基金项目(No.41690134,No.41672139)、国家科技重大专项(2016ZX05034-002-003)和中国地质调查项目(DD20190561-1)资助。

Pore structure and adsorption capacity of shale in the Lower Cambrian Shuijingtuo Formation in the southern flank of Huangling anticline,western Hubei

He Jing1, He Sheng1, Liu Zaoxue2, Zhai Gangyi3, Wang Yi2, Han Yuanjia1, Wan Kuo1, Wei Sile1   

  1. 1. Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences, Hubei Wuhan 430074, China;
    2. Hubei Institute of Geological Survey, Hubei Wuhan 430030, China;
    3. Oil&Gas Survey Center, China Geological Survey, Beijing 100029, China
  • Received:2019-05-24 Revised:2019-11-22 Online:2020-01-25 Published:2020-02-06

摘要:

以鄂西黄陵背斜南翼秭地2井下寒武统水井沱组海相富有机质页岩为研究对象,在水井沱组一段和二段选取代表性页岩样品,利用CO2和N2物理吸附、高压压汞、氩离子抛光-场发射扫描电镜(FE-SEM)等多尺度孔隙结构测试技术和观察手段以及有机质孔统计分析方法,结合甲烷等温吸附实验以及其他测试手段,描述了页岩地球化学、矿物组成和岩相特征,研究了页岩孔隙类型、孔隙形态、孔径分布和比表面积等孔隙结构参数,分析了页岩甲烷吸附能力,讨论了页岩孔隙发育和孔隙结构的影响因素。研究表明:秭地2井水井沱组一段和二段富有机质黑色页岩成熟度Ro约为2.5%,页岩岩相主要有硅质页岩、混合质页岩和黏土质页岩;页岩有机质孔隙形状多样、边界不规则,孔径偏小,大多孔径<50 nm;无机质孔/缝丰富,成因类型多,孔隙形状多变;页岩微孔(孔径为0.3~2.0 nm)中的有机质微孔十分发育,孔径在2~5 nm介孔中的有机质介孔占有较大比例;孔径>5 nm的介孔+宏孔中的无机质孔隙占优势;页岩比表面积大、对甲烷的吸附能力强;硅质页岩的孔隙结构和吸附能力相对较好;页岩有机碳含量、碳酸盐矿物和黏土矿物含量以及页岩岩相等因素对页岩孔隙发育和孔隙结构有重要影响。

关键词: 黄陵背斜南翼, 宜昌斜坡带, 水井沱组, 海相页岩, 孔隙结构, 吸附能力

Abstract:

Aiming at the marine organic-rich shale in the Lower Cambrian Shuijingtuo Formation in the Well Zidi2 in the southern flank of the Huangling anticline in western Hubei, this study selects shale samples from the first and second members of Shuijingtuo Formation. Using the multi-scale testing techniques such as CO2 and N2 physical absorption, high-pressure mercury injection, and argon ion polishing-field emission scanning electron microscope (FE-SEM) the observation methods for pore structure and the statistical analysis methods of organic pores in combination with methane isothermal adsorption experiments and other basic testing methods, this paper describes the geochemistry, mineral composition and lithofacies characteristics of shale, investigates the pore type, pore shape, pore size distribution and specific surface area of shale and other pore structure parameters, analyzes the methane adsorption capacity of shale, and explores the factors affecting the pore development and pore structure of shale. The research results show that Ro of the organic-rich black shale in the first and second members of Shuijingtuo Formation in the Well Zidi2 is about 2.5%, and the shale lithofacies are mainly siliceous shale, migmatitic shale, and clayey shale; organic pores of shale have various shapes, irregular boundaries, and small pore sizes, most of which have a pore diameter of less than 50 nm. Inorganic pores/seams are abundant, with various types of geneses and variable shapes micropores in shale (pore size of 0.3-2.0 nm) develops well, and organic mesopores occupy a large proportion in mesopores with the pore size of 2-5 nm; inorganic pores are dominant in mesopores with a pore size> 5nm and macropores. Shale has a large specific surface area and strong methane adsorption capacity; the pore structure and adsorption capacity of siliceous shale are even better. The organic carbon content, carbonate mineral and clay mineral content of shale, shale lithofacies and other factors have important effects on the pore development and pore structure of shale.

Key words: southern flank of Huangling anticline, Yichang slope belt, Shuijingtuo Formation, marine shale, pore structure, adsorption capacity

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