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现代地质 ›› 2022, Vol. 36 ›› Issue (04): 1052-1064.DOI: 10.19657/j.geoscience.1000-8527.2022.195

• 油气勘探 • 上一篇    下一篇

青藏高原北部东昆仑地区三叠系页岩成岩作用及其对储层的影响

晁海德1,2(), 陈建洲1,2, 王瑾1,2, 李吉庆1, 王国仓3, 赵洪岳1, 蔡廷俊1, 刘立波1, 李生福1, 任文恺1, 邱亮4   

  1. 1.青海省第四地质勘查院,青海 西宁 810029
    2.青海省页岩气资源重点实验室,青海 西宁 810029
    3.中国科学院西北生态环境资源研究院,甘肃 兰州 730000
    4.中国地质大学(北京) 地球科学与资源学院,北京 100083
  • 收稿日期:2022-01-05 修回日期:2022-02-20 出版日期:2022-08-10 发布日期:2022-09-09
  • 作者简介:晁海德,男,硕士,地质工程师,1987年出生,地质工程专业,主要从事能源矿产勘查及研究。Email: 394262585@qq.com
  • 基金资助:
    青海省地质矿产勘查开发局项目“青海省清洁能源靶区优选”(青地矿科[2020]61);青海省地质矿产勘查开发局项目“青海省清洁能源靶区优选”(青地矿科[2021]61);青海省清洁能源矿产专项“青海省都兰县八宝山地区页岩气调查评价”(2018137090KC054)

Diagenesis of Triassic Shale and Its Influence on Reservoir in East Kunlun, Northern Qinghai-Tibetan Plateau

CHAO Haide1,2(), CHEN Jianzhou1,2, WANG Jin1,2, LI Jiqing1, WANG Guocang3, ZHAO Hongyue1, CAI Tingjun1, LIU Libo1, LI Shengfu1, REN Wenkai1, QIU Liang4   

  1. 1. The Fourth Geological Exploration Institute of Qinghai Province, Xining,Qinghai 810029, China
    2. Key Laboratory of Shale Gas Resources of Qinghai Province, Xining,Qinghai 810029, China
    3. Northwest Institute of Ecological Environment and Resources of Chinese Academy of Sciences, Lanzhou,Gansu 730000, China
    4. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
  • Received:2022-01-05 Revised:2022-02-20 Online:2022-08-10 Published:2022-09-09

摘要:

青藏高原北部东昆仑地区八宝山盆地作为高原页岩气成藏特征探索的典型区域之一,对影响储层储集性能的关键因素——成岩作用的研究程度很低,不足以更大限度地发挥其勘探价值。基于岩性观察及薄片、铸体薄片、扫描电镜、X-射线衍射等实验分析资料,对该区三叠系页岩成岩作用及对储层的影响开展研究,结果显示,三叠系八宝山组页岩成岩作用共有6类:压实、胶结、黏土矿物转化、交代、溶蚀及有机质热成熟作用。综合有机质成熟度、岩石热解最高峰温、伊蒙混层比中蒙皂石占比、黏土矿物组合、孔隙类型等指标得出:研究区页岩处于中成岩B期-晚成岩阶段。结合各成岩作用对储层孔隙度的影响,研究区压实作用、胶结作用、黏土矿物转化作用易于造成孔隙度的减小,溶蚀作用、有机质热成熟作用易于孔隙度的增大,而交代作用对孔隙影响小。

关键词: 东昆仑, 三叠系, 成岩作用, 储层影响因素

Abstract:

As a typical area to study shale gas reservoir characteristics in the east Kunlun (northern Qinghai-Tibetan Plateau), the research on shale diagenesis for the reservoir properties is inadequate with limiting its exploration potential. Based on petrographic observation and experimental analyses including thin section microscopy, cast thin section, scanning electron microscope (SEM) and X-ray diffraction (XRD), we studied the Triassic shale diagenesis and its impact on reservoir characteristics. The results show six types of Babaoshan Formation shale diagenesis: compaction, cementation, clay mineral transformation, metasomatism, dissolution, and thermal maturation of organic matter. Based on indicators such as organic matter maturity, rock pyrolysis peaks, smectite ratio in illite-montmorillonite mixed layer, clay mineral assemblage and pore type, we concluded that the studied shale is in the middle diagenetic stage B-late diagenetic stage. Combined with the influence of diagenetic on reservoir, compaction, cementation and clay mineral transformation can readily reduce porosity, dissolution and thermal maturation of organic matter can increase up porosity, while metasomatism has little effect on porosity.

Key words: east Kunlun, Triassic system, diagenesis, influencing factors on reservoirs

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