石油学报 ›› 2025, Vol. 46 ›› Issue (7): 1355-1368.DOI: 10.7623/syxb202507009

• 地质勘探 • 上一篇    

陆相页岩油微观赋存特征与自封闭机理——以准噶尔盆地吉木萨尔凹陷芦草沟组为例

刘金1,2,3, 曹剑1, 王剑2,3, 费李莹2, 魏超1, 仰云峰4, 汤文浩4, 肖佃师5, 钱永新2   

  1. 1. 南京大学地球科学与工程学院 江苏南京 210023;
    2. 中国石油新疆油田分公司勘探开发研究院 新疆克拉玛依 834000;
    3. 新疆页岩油勘探开发重点实验室 新疆克拉玛依 834000;
    4. 苏州冠德能源科技有限公司 江苏苏州 215000;
    5. 中国石油大学(华东)地球科学与技术学院 山东青岛 266580
  • 收稿日期:2025-03-03 修回日期:2025-06-05 发布日期:2025-08-08
  • 通讯作者: 曹剑,男,1978年10月生,2005年获南京大学博士学位,现为南京大学地球科学与工程学院教授,主要从事石油地质学与有机地球化学的研究和教学工作。Email:jcao@nju.edu.cn
  • 作者简介:刘金,男,1989年12月生,2015年获中国石油大学(华东)硕士学位,现为南京大学地球科学与工程学院博士研究生,主要从事非常规油气地质与实验地球化学研究。Email:liujin2015@petrochina.com.cn
  • 基金资助:
    国家自然科学基金重点项目(No.42230808)资助。

Microscopic occurrence and self-containment mechanism of continental shale oil: case study of Lucaogou Formation in Jimusaer sag, Junggar Basin

Liu Jin1,2,3, Cao Jian1, Wang Jian2,3, Fei Liying2, Wei Chao1, Yang Yunfeng4, Tang Wenhao4, Xiao Dianshi5, Qian Yongxin2   

  1. 1. School of Earth Sciences and Engineering, Nanjing University, Jiangsu Nanjing 210023, China;
    2. Research Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, Xinjiang Karamay 834000, China;
    3. Key Laboratory of Xinjiang Shale Oil Exploration and Development, Xinjiang Karamay 834000, China;
    4. Suzhou Guande Energy Technology Co., Ltd., Jiangsu Suzhou 215000, China;
    5. School of Geosciences, China University of Petroleum, Shandong Qingdao 266580, China
  • Received:2025-03-03 Revised:2025-06-05 Published:2025-08-08

摘要: 陆相页岩储层非均质性强,页岩油微观赋存特征复杂、自封闭机理不明,限制了页岩油富集理论认识。以准噶尔盆地吉木萨尔凹陷芦草沟组为例,基于场发射扫描电镜、二维核磁共振、激光扫描共聚焦显微镜、低温N2吸附实验、索氏分步抽提-傅里叶变换红外光谱等分析手段,对页岩油赋存特征与自封闭机理进行了研究。结果表明:①页岩油具有“洋葱皮”状赋存模型,即在大孔(孔径≥2 μm)内有轻质组分和孤立状孔隙水赋存于孔隙中心,而重质组分则以薄膜状赋存于孔隙表面,在小孔(孔径<2 μm)内充填重质组分;②页岩油甜点储层的含油孔径下限为油分子级,可达2~3 nm;③陆相页岩储层内的流体微观赋存模式受生烃超压微运移-油水竞争性吸附置换-多期油气连续充注以及流体与孔隙的相互耦合共同控制,页岩油自封闭作用包括孔隙界面吸附自封闭和孔隙结构-流体赋存相互耦合自封闭。陆相页岩油的衰竭式开采在可动用孔隙尺度及流体组分上具有梯次性和阶段性特点。

关键词: 页岩油, 赋存状态, 赋存机理, 自封闭作用, 吉木萨尔凹陷, 芦草沟组, 准噶尔盆地

Abstract: The enrichment theories of continental shale oil reservoirs are understudied due to its strong heterogeneity, complex microscopic oil occurrence, and unclear self-containment mechanisms. This paper is a case study of Lucaogou Formation in Jimusaer sag, Junggar Basin. Based on field emission scanning electron microscopy (FE-SEM), two-dimensional nuclear magnetic resonance (NMR), laser scanning confocal microscope (LSCM), low-temperature nitrogen adsorption experiments, and Soxhlet stepwise extraction combined with Fourier transform infrared spectroscopy (FTIR) analysis, the occurrence characteristics and self-containment mechanism of shale oil were systematically investigated. The research results show as follows. (1) Shale oil exhibits an onion skin-like occurrence model. Light components and isolated pore water occupy the centers of macropores (pore diameter greater than or equal to 2 μm), while heavy components oil occur as film-like coatings on pore surfaces. Micropores (pore diameter less than 2 μm) are filled with heavy components. (2) There are molecular-scale pores in shale oil sweet-spot reservoirs, with the minimum size ranging from 2 nm to 3 nm. (3) The microscale fluid occurrence patterns in continental shale reservoirs are governed by the factors including hydrocarbon-generating overpressure-driven micro-migration, oil-water competitive adsorption and displacement, multi-stage continuous hydrocarbon charging, and fluid-pore coupling. Shale oil accumulation involves two microscopic self-containment mechanisms based on interfacial adsorption and pore structure-fluid occurrence coupling. The depletion development of continental shale oil demonstrates gradational and staged characteristics in terms of producible pore scales and fluid components.

Key words: shale oil, occurrence state, occurrence mechanism, self-containment, Jimusaer sag, Lucaogou Formation, Junggar Basin

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