孔径分布表征方式对孔隙结构解释的影响

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孔径分布表征方式对孔隙结构解释的影响

Advances in Geo-Energy Research, 2019, 3(2): 187-197

原文网址: https://www.yandy-ager.com/index.php/ager/article/view/117

        氮气吸附和高压亚汞目前已经成为分析非常规页岩油气地层孔隙结构的主要手段。通过这些方法可以得知页岩的孔隙体积，比表面积，孔径分布。对于孔径分布，在以往的研究中，不同的学者采用的不同的表达方式，但是很少有学者对这些表达方式进行过分析对比。

       近日，美国北达科他大学的 Mehdi 教授和刘扣其博士对这一问题进行了研究。他们使用了氮气吸附和高压压汞实验研究了美国巴肯地区的页岩样品，并采用了三种不同的孔径表达方式进行了描述和对比。通过对特征峰的位置，孔隙的聚类以及孔隙结构的非均质性分析，阐述了不同表达方式对孔隙结构解释的影响。研究结果表明，DV/Dd 能有效的表达小孔范围内的孔隙尺寸分布而DV/Dlogd则能突出页岩内的大孔结构。

The impact of pore size distribution data presentation format on pore structure interpretation of shales

Kouqi Liu, Mehdi Ostadhassan

(Published: 2019-03-29)

CorrespondingAuthor and Email:

Mehdi Ostadhassan, mehdi.ostadhassan@und.edu;

ORCID: https://orcid.org/0000-0001-9235-4399

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Citation: Liu, K., Ostadhassan, M. The impact of pore size distribution data presentation format on pore structure interpretation of shales. Advances in Geo-Energy Research, 2019, 3(2): 187-197, doi: 10.26804/ager.2019.02.08.

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ArticleType: Original article

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Abstract：

    A deeper understanding of pore structures in unconventional shale plays can lead to a better evaluation of storage and transport capacity in these complicated rock types. This task is usually done through pore size distribution (PSD) analysis. In this study, N2 adsorption and high-pressure mercury intrusion porosimetry (MIP) were employed to investigate several shale samples. Three different mathematical forms of PSD data presentation: Incremental pore volume versus diameter (DV), differential pore volume versus diameter (DV/Dd) and the log differential pore volume versus diameter (DV/Dlogd), were used to analyze pore structures from these two different methods. The comparison of the results showed that each form of PSD data presentation could demonstrate various types of important pore information. The DV curve is significantly dependent on the experimental data points’ spacing while the other two are not affected. The DV/Dd curve would incite the existence of smaller pore ranges while the DV/Dlogd would embolden larger pore ranges. Additionally, multifractal analysis from each data presentation style illustrated that the heterogeneity index of PSD calculated from the DV/Dd curve is much significant than the one obtained from the DV/Dlogd curve. DV/Dd is more appropriate to be used for characterizing PSD data from N2 adsorption while DV/Dlogd is preferred when MIP data is collected from larger pores.

Keywords: Pore size distribution, different presentations, multifractal, gas adsorption, mercury intrusion.