石油与天然气地质 ›› 2020, Vol. 41 ›› Issue (2): 295-304.doi: 10.11743/ogg20200206

• 油气地质 • 上一篇    下一篇

库车坳陷下侏罗统阿合组致密砂岩储层孔隙微观结构特征及其对致密气富集的控制作用

王朋1,2(), 孙灵辉2,3, 王核1, 李自安1,*()   

  1. 1. 中国科学院 广州地球化学研究所, 广东 广州 510640
    2. 中国科学院 研究生院, 北京 100864
    3. 中国石油 勘探开发研究院, 北京 100083
  • 收稿日期:2019-07-23 出版日期:2020-04-28 发布日期:2020-04-03
  • 通讯作者: 李自安 E-mail:wangpeng@petrochina.com.cn;lizian88@126.com
  • 第一作者简介:王朋(1981-),男,博士,构造地质学。E-mail:wangpeng@petrochina.com.cn

Microscopic pore structure of Ahe tight sand gas reservoirs of the Low Jurassic in Kuqa Depression and its controls on tight gas enrichment

Peng Wang1,2(), Linghui Sun2,3, He Wang1, Zi'an Li1,*()   

  1. 1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, China
    2. Graduate School of Chinese Academy of Sciences, Beijing 100864, China
    3. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
  • Received:2019-07-23 Online:2020-04-28 Published:2020-04-03
  • Contact: Zi'an Li E-mail:wangpeng@petrochina.com.cn;lizian88@126.com

摘要:

库车坳陷是近年来塔里木盆地深层致密砂岩气勘探的重要领域。通过开展物性测试、铸体薄片镜下鉴定、常规压汞实验、微米CT扫描实验及包裹体测试,分析库车坳陷迪北致密砂岩气藏下侏罗统阿合组致密砂岩储层孔隙微观结构特征,结合测井解释结果和包裹体实验,探讨孔隙微观结构对致密砂岩气富集的控制作用。结果表明:库车坳陷下侏罗统阿合组致密储层主要发育溶蚀孔隙(包括长石和岩屑等粒内溶孔、胶结物溶孔)和微裂缝,残余粒间孔隙较少。阿合组致密储层孔隙微观结构可分为3类:第一类主要发育在粗砂岩中,孔喉分选差、孔喉半径大但孔喉比小,孔喉系统为毛细管束状,具有较好的渗流能力;第二类主要发育在粗-细砂岩中,孔喉分选较差,孔喉半径小于第一类储层但孔喉比大,孔喉系统为墨水瓶状;第三类主要发育在细-粉砂岩中,孔喉分选相对较好,孔喉半径小于第二类储层,孔喉系统也表现为墨水瓶状,但渗流能力差。第一类孔喉系统可形成天然气在致密储层中的运移通道;第二类孔喉系统是致密砂岩气主要的储集空间,有利于致密砂岩气的聚集;第三类储层为无效储层,无天然气充注。

关键词: 孔隙微观结构, 致密砂岩气, 阿合组, 下侏罗统, 库车坳陷, 塔里木盆地

Abstract:

Kuqa Depression has been an important region for exploring deep tight sand gas reservoirs in the Tarim Basin during the past few years.The study aims to discuss the micro-structure features of the Ahe tight sandstone reservoirs in the Dibei tight sand gas pool in the Kuqa Depression via reservoir property and inclusion tests, casting thin section observation, MIP(mercury intrusion porosimetry), as well as x-ray micro-CT scanning.What's more, combined with logging interpretation and fluid inclusion data, the controlling effect of microscopic pore structure on tight sand gas enrichment is revealed.The results show that the tight sand reservoirs in the Lower Jurassic Ahe Formation is characterized by a majority of dissolved pores(including intragranular dissolved pores in feldspar, lithic debris, and dissolved pores in cements)and micro-fractures, together with limited residual intergranular pores.The micro-structure of the Ahe sand reservoir pores can be classified into three types.Specifically, type one mainly developed in coarse-grained sandstones is characterized by capillary bundle-shaped pore system, with poor pore throat sorting, large pore throat radius but low pore-throat ratio, and relatively high permeability; type two mainly occurring in the coarse-to-fine grained sandstones is characterized ink-bottle-shaped pore system with relatively poor pore throat sorting, pore throat radius smaller than that of type one mentioned above but large pore-throat ratio; type three mainly appearing in fine-to-silty sandstone also has ink-bottle-shaped pore throat system with relatively good pore throat sorting and pore throat radius smaller than that of type two and low permeability.Type one pore structure can serve as the pathway for tight gas migration, type two is favorable for tight sand gas enrichment, while type three reservoir has no gas charging.

Key words: microscopic pore structure, tight sand gas, Ahe Formation, Lower Jurassic, Kuqa Depression, Tarim Basin

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