石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (4): 910-922.doi: 10.11743/ogg20230409

• 油气地质 • 上一篇    下一篇

陆相页岩游离油定量表征及其影响因素

刘天1,2(), 刘小平1,2(), 刘启东3, 段宏亮3, 刘世丽3, 孙彪1,2, 化祖献1,2   

  1. 1.中国石油大学(北京) 油气资源与工程全国重点实验室,北京 102249
    2.中国石油大学(北京) 地球科学学院,北京 102249
    3.中国石化 江苏油田分公司 勘探开发研究院,江苏 扬州 225009
  • 收稿日期:2023-02-23 修回日期:2023-06-17 出版日期:2023-08-01 发布日期:2023-08-09
  • 通讯作者: 刘小平 E-mail:13804341768@163.com;liuxiaoping@cup.edu.cn
  • 第一作者简介:刘天(1997—),男,博士研究生,非常规油气地质。E?mail: 13804341768@163.com
  • 基金项目:
    国家自然科学基金项目(42072150)

Quantitative characterization and influencing factors of free oil content in lacustrine shale: A case study of Funing Formation in the Gaoyou Sag, Subei Basin

Tian LIU1,2(), Xiaoping LIU1,2(), Qidong LIU3, Hongliang DUAN3, Shili LI3, Biao SUN1,2, ZuXian HUA1,2   

  1. 1.National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum (Beijing),Beijing 102249,China
    2.College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China
    3.Research Institute of Exploration and Development,SINOPEC Jiangsu Oilfield Company,Yangzhou,Jiangsu 225009,China
  • Received:2023-02-23 Revised:2023-06-17 Online:2023-08-01 Published:2023-08-09
  • Contact: Xiaoping LIU E-mail:13804341768@163.com;liuxiaoping@cup.edu.cn

摘要:

为准确、定量评价陆相页岩游离油量及其影响因素,选取了苏北盆地高邮凹陷古近系阜宁组二段陆相页岩样品,利用全岩X射线衍射分析、有机碳测定、多温阶热释烃、高压压汞、有机质抽提和二维核磁共振等实验技术手段,分析了页岩样品矿物成分、生烃品质、孔隙结构和含油性等特征。结果表明,页岩富含石英、长石、方解石、白云石以及黏土矿物等成分;总有机碳含量(TOC)为0.61 % ~ 3.70 %,镜质体反射率(Ro)为0.70 %~0.72 %,处于成熟阶段;储集空间主要为晶间孔、粒间孔和有机孔。二维核磁共振可以有效表征页岩游离油赋存状态。抽提分离出页岩储层内可动用的游离态轻、重烃类化合物和可溶有机质,对抽提前、后页岩样品进行二维核磁共振谱图分析,将谱图划分出轻质油和类固体有机质等区域。抽提后类固体有机质含量和TOC有良好相关关系,抽提前核磁轻质烃含量和核磁轻质烃抽提差都与热解游离油量有较好线性关系。游离油量随着长英质矿物含量增加先增大后减小,与TOC含量整体上为正相关关系;Ⅰ型和Ⅱ1型干酪根有机质页岩游离油量较其他类型高;适中的成熟度演化使干酪根生成烃类轻组分增多、可动性增强,游离油量增多。高孔隙度、高比孔体积及高孔喉半径均值的页岩储层有利于游离油富集。

关键词: 游离油量, 核磁共振, 阜宁组, 陆相页岩, 高邮凹陷, 苏北盆地

Abstract:

The lacustrine shale samples were selected from the second member of the Funing Formation in Gaoyou Sag, Subei Basin, to precisely and quantitatively evaluate the free oil content and its controlling factors of lacustrine shale. The mineral composition, hydrocarbon generation capacity, pore structure, oil-bearing properties, and other characteristics of the samples were analyzed using X-ray diffraction tests, TOC content measurement, multistep rock-eval pyrolysis, high pressure mercury injection, organic matter extraction and 2D NMR. The results show that the shale is rich in quartz, feldspar, calcite, dolomite, clay, and other minerals. The TOC is between 0.61 % and 3.70 %. The Ro is between 0.70 % and 0.72 %, indicating the source rocks being in the mature stage. The reservoir space is mainly composed of intergranular and organic pores. Two-dimensional NMR, which can efficiently detect and characterize the occurrence of free oil, was employed to help extracting free light and heavy hydrocarbons as well as soluble organic matter from the samples, and performing spectra analysis before and after the extraction, on which light oil zone, solid organic matter zone, hydroxyl compound zone, and water zone were identified. Post-extraction solid organic matter content was found to have a good correlation with TOC. Pre-extraction NMR-based light hydrocarbon content and NMR-based differential light hydrocarbon content between pre-extraction and post-extraction show a relatively strong linear connection with pyrolysis free oil content. The free oil content rises initially and then fall as the felsic mineral content rises, and it is positively correlated with TOC as a whole. The free oil contents in type Ⅰ and Ⅱ1 kerogen source rocks are higher than those of other kinds. The right degree of thermal evolution of source rocks increases the ratio of light hydrocarbons and mobility of kerogen-generated hydrocarbons, as well as free oil content. Shale reservoirs with high porosity, specific pore volume, and median value of pore throat radius are conducive to free oil enrichment.

Key words: free oil content, nuclear magnetic resonance, Funing Formation, lacustrine shale, Gaoyou Sag, Subei Basin

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