4.6 Article

Identifying Organic Matter (OM) Types and Characterizing OM Pores in the Wufeng-Longmaxi Shales

期刊

ACS OMEGA
卷 -, 期 -, 页码 -

出版社

AMER CHEMICAL SOC
DOI: 10.1021/acsomega.2c04497

关键词

-

资金

  1. Natural Science Foundation of Anhui Province
  2. National Natural Science Foundation of China
  3. Key Programs of the Tongling University
  4. Starting Research Fund from the Tongling University
  5. [2208085QD110]
  6. [42207293]
  7. [2021tlxyZD03]
  8. [2021tlxyrc16]

向作者/读者索取更多资源

This study investigated different organic matter pores in the Longmaxi Formation shales in the Sichuan Basin using optical microscope, SEM, and adsorption experiments. The results showed that pyrobitumen and quartz-rich brittle shale play significant roles in pore development, while pores in organic matter like microorganisms and algae are mainly mesopores.
Organic matter (OM) pores are considered to be an important pore type in the Ordovician Wufeng-Silurian Longmaxi Formation shales in the Sichuan Basin, China, because they have a high capacity to store natural gas. However, to the best of our knowledge, research on the characterization and quantitation of different OM pore characteristics is insufficient. In this study, detailed optical microscope and scanning electron microscope (SEM) observations and the pores/particles and cracks analysis system (PCAS) were applied to identify the OM pores and obtain quantitative information on pores such as pore size, surface porosity, form factor, and probability entropy. Moreover, CO2 and N2 adsorption experiments were performed to study the properties of pores for samples with different TOC and mineral compositions. The results show the following. (1) Pyrobitumen and kerogen can be distinguished under an optical microscope and SEM; the former can be further divided into pyrobitumen without a fixed shape and pyrobitumen with a certain shape, and the latter contains algal fragments, bacteria-like aggregates, graptolite, and micrinite. The overwhelming number of SEM-visible OM pores are mainly observed in pyrobitumen without a fixed shape, whereas pores in other OM types are complex. A PCAS analysis showed that mesomacropores are developed in pyrobitumen without a fixed shape, whereas pores in algal fragments and bacterial-like aggregates are mainly mesopores. (2) Quartz-rich brittle shale will provide more visible SEM pores compared to clay-rich ductile shale, and carbonates are unfavorable for pore development because they can block the pore as cements. Moreover, the rigid mineral framework, including that constructed by quartz recrystallization and pyrite cementation, and the pore-fluid pressure are favorable for the development of OM pores. (3) Adsorption experiments showed that pyrobitumen makes a great contribution to pore development, including micropores and meso-/macropores. Finally, we propose that the pore parameters (e.g., pore diameter, pore form factor, and deformation) of pyrobitumen without a fixed shape may characterize the enrichment condition of shale gas.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.6
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据