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J4 ›› 2016, Vol. 22 ›› Issue (1): 159-.DOI: 10.16108/j.issn1006-7493.

• 页岩气专栏 • 上一篇    下一篇

宁镇地区下志留统高家边组富有机质页岩孔隙结构

李晋宁,姚素平*,孙超,丁海   

  • 出版日期:2016-03-20 发布日期:2016-04-14

Pore Structure of Organic-rich Shales in the Lower Silurian Gaojiabian Formation from Ningzhen Area,Jiangsu Province

LI Jinning, YAO Suping*, SUN Chao, DING Hai   

  • Online:2016-03-20 Published:2016-04-14

摘要:

通过氩离子抛光-场发射扫描电镜、小角X射线散射及低温氮气吸附实验,对宁镇地区下志留统仑山5井等高家边组
底部富有机质泥页岩孔隙结构进行分析,为下扬子区下志留统富有机质泥页岩的储层评价提供依据。研究表明:高家边组
富有机质泥页岩含有大量的纳米级孔隙,包括有机质孔、矿物粒间孔、矿物粒内孔、微裂缝等,孔径分布复杂;优势孔径
分布为介孔段,孔隙直径主要为2~50 nm。影响孔径分布的主要因素是矿物组成,脆性矿物和黏土矿物对微孔和介孔都有
一定的影响,而有机质含量对泥页岩总体孔隙特征的影响并不明显。

关键词: 宁镇地区, 高家边组, 氩离子抛光-场发射扫描电镜, 小角X射线散射, 低温氮气吸附, 孔隙结构

Abstract:

To provide data for the reservoir evaluation of the lower Silurian organic-rich shales in the Lower Yangtze Region, in this
study we analyze the characteristics of pore structures of the shales based on the study of samples from the LunShan 5 well in the
Ningzhen Area. Comprehensive methods were employed, mainly including field emission scanning electron microscopy (FE-SEM),
small angle X-ray scattering (SAXS) and low-temperature nitrogen adsorption(LT-N2GA). Results indicate that the pores in the shales
are generally nanoscale and can be classified into four types in general, i.e., organic pores, interparticle pores, mineral matrix pores and
microfractures. The interparticle pores dominate among these multiple types of pores. The pore size distribution of the shales are
complex, as mesopores (2~50 nm) were distributed most widely and some micropores (<2 nm) and macropores (>50 nm) have also
been observed. In terms of the controls of the pore size distribution of the shales, we conduct a correlation between pore volume and
brittle minerals (e.g., quartz, pyrite and albite) contents, clay contents and TOC. It is implied that mineral compositions are the primary
control, contents of brittle minerals and clay minerals also play a certain influence (especially for micropores and mesopores), whereas
TOC has the least impacts.

Key words: Ningzhen Area;Gaojiabian Formation;field emission scanning electron microscopy(FE-SEM);small angle X-ray scattering(SAXS);low-temperature nitrogen adsorption(LT-N2GA);pore structure.