西南石油大学学报(自然科学版) ›› 2018, Vol. 40 ›› Issue (4): 29-39.DOI: 10.11885/j.issn.1674-5086.2016.08.08.01

• 地质勘探 • 上一篇    下一篇

渝东南武隆地区龙马溪组页岩孔裂隙特征研究

张颖, 张海涛, 何希鹏, 高玉巧, 张培先   

  1. 中国石化华东油气分公司, 江苏 南京 210000
  • 收稿日期:2016-08-08 出版日期:2018-08-01 发布日期:2018-08-01
  • 通讯作者: 张海涛,E-mail:haitao_zhang@cumt.edu.cn
  • 作者简介:张颖,1989年生,女,汉族,山东济宁人,工程师,硕士,主要从事石油地质、储层地质学等方面的研究工作。E-mail:912808221@qq.com;张海涛,1987年生,男,汉族,山东威海人,工程师,硕士,主要从事常规与非常规油气地质等方面的研究工作。E-mail:haitao_zhang@cumt.edu.cn;何希鹏,1970年生,男,汉族,云南曲靖人,高级工程师,硕士,主要从事常规与非常规油气地质等方面的研究工作。E-mail:hxpphl@sohu.com;高玉巧,1978年生,女,汉族,山东济宁人,高级工程师,博士,主要从事沉积岩石学与储集层地质学、非常规油气地质等方面的研究工作。E-mail:57488333@qq.com;张培先,1983年生,男,汉族,山东潍坊人,工程师,硕士,主要从事沉积学、非常规油气地质等方面的研究工作。E-mail:491752122@qq.com
  • 基金资助:
    国家科技重大专项(2016ZX05061);中国石化科技项目(P14075)

Shale Pore Characteristics of Longmaxi Formation in Wulong Area, Southeastern Chongqing

ZHANG Ying, ZHANG Haitao, HE Xipeng, GAO Yuqiao, ZHANG Peixian   

  1. East China Company, SINOPEC, Nanjing, Jiangsu 210000, China
  • Received:2016-08-08 Online:2018-08-01 Published:2018-08-01

摘要: 为明确渝东南武隆地区龙马溪组页岩孔裂隙发育特征,利用岩芯观察、氩离子抛光扫描电镜分析、低温氮气吸附脱附实验等方法,结合图像分析技术和分形几何理论,对LY-1井龙马溪组页岩孔隙结构及分形特征进行了研究。结果表明,武隆地区龙马溪组页岩宏观裂隙以层间页理缝和成岩收缩缝为主,扫描电镜下可见粒内孔、粒间孔及有机质孔,有机质孔最为发育,孔径几纳米到几十纳米;低温N2吸附实验结果显示龙马溪组页岩存在3类优势孔径,I类优势孔径分布在1.0~1.5 nm,表明微孔是该区主要的孔隙之一,Ⅱ、Ⅲ类优势孔径分别分布在2.5~3.5 nm、5.0~18.0 nm,孔径>4.0 nm时曲线分维值与TOC、脆性矿物含量及含气量呈负相关性,与黏土矿物呈正相关性。研究认为,有机质孔为页岩气富集提供了最主要的空间,黏土矿物发育复杂结构的孔隙对气体赋存具有一定贡献。

关键词: 龙马溪组, 孔隙结构, 图像分析, 分形理论, 武隆地区

Abstract: Core observation, argon-ion polishing scanning electron microscopy, and low temperature nitrogen adsorption and desorption methods were used to study the pore characteristics of shale in the Longmaxi Formation, Wulong area, southeastern Chongqing. The shale pore structures and fractal features of the LY-1 Well, Longmaxi Formation, were investigated using image analysis technology and the fractal geometry theory. The results show that the macro shale fractures in the area are mainly interlayer lamellation cracks and diagenetic shrink micro-cracks. The intragranular pores, intergranular pores, and organic matter (OM) holes can be observed by the scanning electron microscope. The OM holes, with dimensions from several to dozens of nanometers, develop well, and the low-temperature N2 adsorption results show that the shale in the Longmaxi Formation has three significant pore sizes. The pore size of type I ranges from 1.0 to 1.5 nm, indicating that micropores are the most developed pores in the area. The types Ⅱ and Ⅲ pore sizes are from 2.5 to 3.5 nm and from 5.0 to 18.0 nm. When the pore size >4.0 nm, the curve fractal dimension value has a negative relationship with TOC, brittle mineral and gas contents, and has a positive relationship with clay minerals. The study shows that OM pores provide major reservoir spaces for shale gas, and pores with complex structures in clay minerals make a certain contribution to the shale gas reservoir.

Key words: Longmaxi Formation, pore structure, image analyze, fractal theory, Wulong Area

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