新疆石油地质 ›› 2025, Vol. 46 ›› Issue (5): 521-530.doi: 10.7657/XJPG20250501

• 油气勘探 •    下一篇

黔西地区龙潭组煤系泥页岩储集层孔隙结构及控制因素

李聚豪1(), 何金先1(), 杨兆彪1, 张晓丽1, 吴蒙2, 马丽3, 袁媛4,5, 闻明忠2   

  1. 1.中国矿业大学 a.煤层气资源与成藏过程教育部重点实验室; b.资源与地球科学学院,江苏 徐州 221116
    2.江苏地质矿产设计研究院(中国煤炭地质总局检测中心),江苏 徐州 221006
    3.中国建筑材料工业地质勘查中心山西总队,太原 030031
    4.山西省煤炭地质一一五勘查院有限公司,山西 大同 037000
    5.山西矿区综合监测与应急减灾技术创新中心,山西 大同 037000
  • 收稿日期:2024-12-20 修回日期:2025-02-03 出版日期:2025-10-01 发布日期:2025-09-30
  • 通讯作者: 何金先(1983-),男,广西南宁人,讲师,博士,沉积地质与能源地质,(Tel)13852442691(Email)jxhe@cumt.edu.cn
  • 作者简介:李聚豪(2000-),男,河南信阳人,硕士研究生,地球化学与能源地质,(Tel)15939732256(Email)juhao_li@foxmail.com
  • 基金资助:
    国家重点研发计划项目(2021YFC2902003)

Characteristics and Controlling Factors of Pore Structure in Coal-Measure Shale Reservoirs: Taking Longtan Formation in Western Guizhou as an Example

LI Juhao1(), HE Jinxian1(), YANG Zhaobiao1, ZHANG Xiaoli1, WU Meng2, MA Li3, YUAN Yuan4,5, WEN Mingzhong2   

  1. 1. China University of Mining and Technology, a.MOE Key Laboratory of Coalbed Methane Resources & Reservoir Formation Process; b.School of Resources and Geosciences, Xuzhou, Jiangsu 221116, China
    2. Jiangsu Design Institute of Geology and Mineral Resources / Testing Center of China National Administration of Coal Geology, Xuzhou, Jiangsu 221006, China
    3. Shanxi Branch of China National Geological Exploration Center of Building Materials Industry, Taiyuan, Shanxi 030031, China
    4. Shanxi Coal Geology No.115 Exploration Institute Co., Ltd., Datong, Shanxi 037000, China
    5. Shanxi Technology Innovation Center for Comprehensive Monitoring & Emergency Disaster Mitigation in Mines, Datong, Shanxi 037000, China
  • Received:2024-12-20 Revised:2025-02-03 Online:2025-10-01 Published:2025-09-30

摘要:

孔隙结构影响泥页岩的储气性能,是页岩气资源潜力评价的重要参数。以黔西地区上二叠统龙潭组煤系泥页岩为研究对象,采用电镜扫描对微观孔隙和微裂缝定性观察并划分类型,通过高压压汞和低温氮气吸附实验对微观孔隙结构与孔隙直径分布进行了定量表征,结合有机地球化学参数与矿物组成分布特征分析了煤系泥页岩储集层孔隙结构特征的控制因素。结果表明:龙潭组煤系泥页岩基质孔隙可划分为残余原生粒间孔、矿物铸模孔、黏土矿物间微孔、晶间孔、粒内溶蚀孔和有机质孔,微裂缝以张性微裂缝、剪性微裂缝、层理缝和成岩收缩缝为主;微孔及过渡孔为主要孔隙空间,特别是直径小于5 nm的微孔;孔隙空间类型以墨水瓶孔和“V”字形孔为主,平行狭缝较发育,孔隙连通性较好;总有机碳含量、有机质成熟度以及矿物组成是黔西地区龙潭组煤系泥页岩储集层孔隙结构的主要控制因素,随着总有机碳含量增大,泥页岩单点孔体积和比表面积增大;热演化程度升高对微孔和过渡孔孔容增加有积极贡献;黏土矿物对储集层孔隙结构影响较为复杂;高脆性指数则对储集层中孔、大孔和微裂缝发育有积极影响,有利于页岩气渗流。

关键词: 黔西地区, 龙潭组, 煤系泥页岩, 页岩气, 孔隙结构, 控制因素

Abstract:

Pore structure affects gas storage performance of shale and is an important parameter for evaluating shale gas resource potential. Taking the coal-measure shale of Upper Permian Longtan formation in western Guizhou as an example, micro-pores and micro-fractures were qualitatively observed using scanning electron microscopy (SEM) and classified, and the microscopic pore structure and pore size distribution were quantitatively characterized through high-pressure mercury injection and low-temperature nitrogen adsorption experiments. Combining with organic geochemical parameters and mineral composition distribution characteristics, the factors controlling the pore structures of coal-measure shale reservoirs were identified. The results show that the matrix pores in coal-measure shale of the Longtan formation can be divided into six occurrence types: residual primary intergranular pores, mineral moldic pores, clay mineral intergranular pores, intergranular pores, intragranular dissolution pores, and organic pores, and the micro-fractures are mainly extensional, shear, bedding, and diagenetic shrinkage micro-fractures. Micro-pores (especially those with diameter <5 nm) and transitional pores provide the main pore space. The pore space types are dominated by ink bottle holes and V-shaped holes, with a certain amount of parallel slits, and the connectivity between pores is relatively good. Total organic carbon content (TOC), maturity of organic matter, and mineral composition are the main factors controlling the pore structure of the coal-measure shale reservoirs of Longtan formation in western Guizhou. The single-point pore volume and specific surface area of the shale increase with the increase of TOC. The degree of thermal evolution contributes positively to the increase of micro-pore and transitional pore volume. Clay minerals have complex impacts on the pore structure. High brittleness index has a positive effect on the development of meso-pores, macro-pores and micro-fractures, being conducive to shale gas flow.

Key words: western Guizhou, Longtan formation, coal-measure shale, shale gas, pore structure, controlling factor

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