新疆石油地质 ›› 2023, Vol. 44 ›› Issue (4): 392-403.doi: 10.7657/XJPG20230402

• 油气勘探 • 上一篇    下一篇

川中地区大安寨段陆相页岩岩相对孔隙结构的控制作用

孔祥晔1a,1b(), 曾溅辉1a,1b(), 罗群1c, 谭杰2, 张芮2, 王鑫1a,1b, 王乾右1c   

  1. 1.中国石油大学(北京) a.地球科学学院;b.油气资源与探测国家重点实验室;c.非常规油气科学技术研究院,北京 102249
    2.中国石油 西南油气田分公司 勘探开发研究院,成都 610401
  • 收稿日期:2022-07-01 修回日期:2022-08-09 出版日期:2023-08-01 发布日期:2023-08-01
  • 通讯作者: 曾溅辉(1962-),男,江西新干人,教授,博士,石油地质,(E-mail)zengjh@cup.edu.cn
  • 作者简介:孔祥晔(1990-),男,四川遂宁人,博士研究生,石油地质,(Tel)15611818520(E-mail)kongxiangyecup@163.com
  • 基金资助:
    国家自然科学基金(41972147)

Controls of Continental Shale Lithofacies on Pore Structure of Jurassic Da’anzhai Member in Central Sichuan Basin

KONG Xiangye1a,1b(), ZENG Jianhui1a,1b(), LUO Qun1c, TAN Jie2, ZHANG Rui2, WANG Xin1a,1b, WANG Qianyou1c   

  1. 1. China University of Petroleum (Beijing), a. College of Earth Sciences; b. State Key Laboratory of Oil and Gas Resources and Exploration; c. Research Institute of Unconventional Oil and Gas Science and Technology, Beijing 102249, China
    2. Research Institute of Exploration and Development, Southwest Oil and Gas Field Company, PetroChina, Chengdu, Sichuan 610401, China
  • Received:2022-07-01 Revised:2022-08-09 Online:2023-08-01 Published:2023-08-01

摘要:

页岩储集层的油气储集能力取决于其复杂的孔隙结构,而不同页岩岩相具有不同的孔隙结构特征。为了明确不同页岩岩相对孔隙结构的控制作用,以川中地区侏罗系自流井组大安寨段页岩为例,基于总有机碳含量和X射线衍射全岩矿物分析,确定大安寨段页岩岩相,对不同页岩岩相进行薄片、扫描电镜、低温氮气吸附和高压压汞分析,确定其孔隙结构特征。结果表明,川中地区大安寨段页岩主要发育6种岩相:富有机质黏土质页岩、含有机质黏土质页岩、贫有机质黏土质页岩、含有机质混合质页岩、贫有机质混合质页岩和贫有机质钙质页岩,孔隙形态以平行板状和狭缝状为主。黏土质页岩主要发育黏土矿物层间孔、有机质孔和生烃增压缝,混合质页岩主要发育残余粒间孔,钙质页岩发育少量溶蚀孔。各类页岩岩相的孔体积和比表面积与黏土矿物含量呈正相关,富有机质黏土质页岩大孔孔体积与总有机碳含量呈正相关。其中,富有机质黏土质页岩大孔孔体积最大,孔径分布呈三峰特征,是川中地区大安寨段页岩油储集最为有利的页岩岩相。

关键词: 川中地区, 下侏罗统, 大安寨段, 储集层, 页岩岩相, 孔隙结构, 主控因素

Abstract:

The hydrocarbon storage capacity of shale reservoirs depends on their complex pore structures, which vary by lithofacies of shales. In order to clarify the control of shale lithofacies on the pore structure, the lithofaices of the shales in the Da’anzhai member of Jurassic Ziliujing formation in central Sichuan basin were determined based on total organic carbon and X-ray diffraction analyses, and the pore structure characteristics of the shales were identified by means of thin section observation, and analysis on scanning electron microscopy, low-temperature nitrogen adsorption and high-pressure mercury injection. The results show that six shale lithofacies (organic-rich clayey shale, organic-moderate clayey shale, organic-poor clayey shale, organic-moderate mixed shale, organic-poor mixed shale, and organic-poor calcareous shale) are mainly developed in the Da’anzhai member, with parallel plate-like and slit-like pores dominantly. Clayey shales mainly contain clay mineral interlayer pores, organic matter pores, and fractures induced by hydrocarbon generation pressurization; mixed shale mainly contains residual intergranular pores; and calcareous shale mainly contains a small amount of dissolution pores. For all these lithofacies, the clay mineral content is positively correlated with pore volume and specific surface area, and the TOC is positively correlated with the macropore volume of organic-rich clayey shale. The organic-rich clayey shale exhibits the largest macropore volume and trimodal pore-size distribution, making it the most favorable lithofacies for shale oil storage in the Da’anzhai member in central Sichuan basin.

Key words: central Sichuan basin, Lower Jurassic, Da’anzhai member, reservoir, shale lithofacies, pore structure, controlling factor

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