石油与天然气地质 ›› 2021, Vol. 42 ›› Issue (4): 909-918.doi: 10.11743/ogg20210412

• 油气地质 • 上一篇    下一篇

四川盆地元坝地区自流井组页岩储层孔隙结构特征

姜涛1,2,3,4,5(), 金之钧1,2,3,4,6, 刘光祥3,4, 胡宗全3,4, 刘全有3,4, 刘忠宝3,4, 王鹏威3,4, 王濡岳3,4, 杨滔3,4,7, 王冠平3,4   

  1. 1. 北京大学 造山带与地壳演化教育部重点实验室, 北京 100871
    2. 北京大学 石油与天然气研究中心, 北京 100871
    3. 页岩油气富集机理与有效开发国家重点实验室, 北京 100083
    4. 中国石化 页岩油气重点实验室, 北京 100083
    5. 中国地质科学院, 北京 100037
    6. 北京大学 能源研究院, 北京 100871
    7. 中国石化 河南油田分公司 勘探开发研究院, 河南 郑州 450046
  • 收稿日期:2019-07-25 出版日期:2021-08-28 发布日期:2021-08-27
  • 第一作者简介:姜涛(1988-), 男, 博士研究生, 非常规油气勘探开发。E-mail: jiangtao1988@pku.edu.cn
  • 基金项目:
    国家科技重大专项(2017ZX05036004);中国石油化工股份有限公司技术开发项目(P19017-2)

Pore structure characteristics of shale reservoirs in the Ziliujing Formation in Yuanba area, Sichuan Basin

Tao Jiang1,2,3,4,5(), Zhijun Jin1,2,3,4,6, Guangxiang Liu3,4, Zongquan Hu3,4, Quanyou Liu3,4, Zhongbao Liu3,4, Pengwei Wang3,4, Ruyue Wang3,4, Tao Yang3,4,7, Guanping Wang3,4   

  1. 1. Key Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education, Peking University, Beijing 100871, China
    2. Institute of Oil&Gas, Peking University, Beijing 100871, China
    3. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China
    4. Key Laboratory of Shale Oil/Gas Exploration and Production, SINOPEC, Beijing 100083, China
    5. Chinese Academy of Geological Sciences, Beijing 100037, China
    6. Institute of Energy, Peking University, Beijing 100871, China
    7. Exploration and Development Research Institute of Henan Oilfield Branch Company, SINOPEC, Zhengzhou, Henan 450046, China
  • Received:2019-07-25 Online:2021-08-28 Published:2021-08-27

摘要:

四川盆地元坝地区自流井组页岩是陆相页岩气的主要研究层段之一,目前正处于勘探攻关的重要阶段。页岩孔隙结构是评价页岩储层储集能力的重要指标,是明确页岩气富集机理的关键。采用总有机碳含量、全岩X衍射、N2吸附-高压压汞孔径联合实验及氩离子抛光-扫描电镜等多种实验测试方法对其孔隙结构进行了定量表征。结果表明:自流井组页岩粘土矿物含量高,介于38.8%~67.3%,平均为52.8%。孔隙类型以矿物基质孔隙为主,有机质孔次之,微裂缝局部发育;N2吸附滞后环反应主要发育平行板状狭缝型孔隙,同时含有少量墨水瓶型孔;主要孔径分布区间为中孔,大安寨段与东岳庙段相比,由于微孔比例偏低,宏孔比例偏高,所以中值孔径与孔体积较大、比表面积相对较小。自流井组页岩储层孔体积与比表面积主要由粘土矿物决定,孔体积和比表面积与TOC呈负相关或无关,主要由于有机质内镜质体与丝质体不发育孔隙,以及可溶有机质对孔体积和吸附位的占据。研究成果对研究区陆相页岩气的研究与勘探具有重要的借鉴和指导意义。

关键词: 孔隙结构, 定量表征, 陆相页岩储层, 自流井组, 元坝地区, 四川盆地

Abstract:

Shale of the Ziliujing Formation in Yuanba area of Sichuan Basin, currently at a critical stage of exploration, is one of the main research targets of terrestrial shale gas.As a significant index to evaluate the storage capacity of shale reservoirs, shale pore structure is the key to clarify the enrichment mechanism of shale gas.In this study, the pore structure is quantitatively characterized through an integration of total organic carbon (TOC) content tests, whole rock X-ray diffraction, combined experiment of N2 adsorption and high-pressure mercury intrusion for pore size and scanning electron microscopy (SEM) after argon ion milling.The results show that the Ziliujing Formation shale is dominated by clay minerals, accounting for 38.8% to 67.3% with an average of 52.8%;the pores are mainly matrix pores, followed by organic pores, and with micro-fractures developed locally.The hysteresis loops of N2 adsorption reflect the well development of parallel plate-like slit pores together with a small amount of ink bottle-shaped pores.The main interval of pore size distribution falls in mesopores.Compared with Dongyuemiao Member, Da'anzhai Member contains fewer micropores and more macropores, leading to a higher median value of pore size and pore volume, while a relatively smaller specific surface area (SSA).The pore volume and SSA of shale reservoirs in the Ziliujing Formation depend on clay minerals.The pore volume and SSA are in a negative correlation or irrelevant with the TOC content, mainly due to the infertility of organic pores in vitrinite and filament and the occupation of pore volume and adsorption sites by soluble organic matters.These will be of referential significance to the exploration of terrestrial shale gas in the study area.

Key words: pore structure, quantitative characterization, terrestrial shale reservoir, Ziliujing Formation, Yuanba area, Sichuan Basin

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