Organic matter (OM)-hosted pores are important constituents of the pore system of black shales and play a crucial role in determining their methane adsorption capacity and porosity. OM-hosted pores are generally observed and described with scanning electron microscope (SEM) on Ar ion-milled surfaces. However, SEM imaging is not able to reliably distinguish OM types and relate the observed pores to specific macerals. Partly because of this inability to relate organic pores to macerals, the evolution of organic porosity during thermal maturation remains poorly understood.

In this paper, we review the petrographic characteristics of dispersed organic matter (DOM) in black shales under the SEM. Organic petrographic classification of DOM developed for reflected-light microscopy is so far the most practical method when describing DOM in black shales under the SEM because this classification has information on the origin of DOM. Therefore, correlative microscopy (combination of reflected-light and electron microscopy) is the most effective method to identify both OM types and OM-hosted pores. This method, however, is not readily available to most researchers. Although identifying OM on the basis of SEM observations is a challenging task, it is achievable provided there is a good understanding of the studied shales, especially their thermal maturity and original OM composition. Therefore, the overall objective of this paper is to review petrographic characteristics of DOM in black shales under the SEM to provide some guidelines for identifying DOM from SEM observations.

We also review factors that control the formation and preservation of OM-hosted pores. OM-hosted pores consist of primary and secondary organic pores. Primary organic pores are pores inherited from the biological structure of the original OM. Secondary organic pores develop during hydrocarbon generation and expulsion from oil-prone OM and are hosted by solid bitumen or pyrobitumen. The development of secondary organic pores is controlled by thermal maturity and OM type, and their preservation is subject to thermal maturity, OM content, and mineralogical composition.

The presented view of the evolution of micropore and mesopore characteristics of OM with thermal maturity is based on data from the literature. The specific surface area and pore volume of OM in black shales follow parabolic patterns with increasing thermal maturity (quantified via vitrinite reflectance, R_o). The initial increase reflects development of OM-hosted pores, and the subsequent decrease is due to denser stacking of aromatic units in the macromolecular structure of OM, with maximum values (specific surface area ~ 300 m²/g and pore volume ~ 0.3 cm³/g) reached at R_o values in the 2.5–3.5% range. The contribution of OM-hosted pores to the pore characteristics of black shales depends on OM content, OM type, and thermal maturity.

有机质（OM）承载的孔隙是黑色页岩孔隙系统的重要组成部分，在决定其甲烷吸附能力和孔隙度方面起着至关重要的作用。通常使用扫描电子显微镜 (SEM) 在 Ar 离子研磨表面上观察和描述 OM 承载的孔。然而，SEM 成像无法可靠地区分 OM 类型并将观察到的孔隙与特定的微晶联系起来。部分由于无法将有机孔隙与微晶相联系，热成熟过程中有机孔隙度的演变仍然知之甚少。

在本文中，我们回顾了扫描电镜下黑色页岩中分散有机质 (DOM) 的岩相特征。为反射光显微镜开发的 DOM 有机岩相分类是迄今为止在 SEM 下描述黑色页岩中的 DOM 时最实用的方法，因为该分类具有关于 DOM 来源的信息。因此，相关显微镜（反射光和电子显微镜的组合）是识别 OM 类型和 OM 托管孔隙的最有效方法。然而，这种方法对于大多数研究人员来说并不容易获得。尽管基于 SEM 观察识别 OM 是一项具有挑战性的任务，但只要对所研究的页岩有很好的了解，尤其是它们的热成熟度和原始 OM 组成，这是可以实现的。所以，

我们还回顾了控制 OM 承载孔形成和保存的因素。OM 赋存的孔隙由原生有机孔隙和次生有机孔隙组成。原生有机孔是从原始有机质的生物结构中继承而来的孔。次生有机孔在油气生成和从易油 OM 中排出的过程中发育，并以固体沥青或焦沥青为主体。次生有机孔的发育受热成熟度和有机质类型的控制，其保存受热成熟度、有机质含量和矿物组成的影响。

OM 的微孔和中孔特征随热成熟度演变的观点基于文献数据。随着热成熟度的增加，黑色页岩中 OM 的比表面积和孔体积遵循抛物线模式（通过镜质反射率，R _o量化）。最初的增加反映了 OM 承载孔的发展，随后的减少是由于 OM 大分子结构中芳香单元的更密集堆积，最大值（比表面积 ~ 300 m ² /g 和孔体积 ~ 0.3 cm ³ /g) 达到 R _o值在 2.5-3.5% 范围内。OM 赋存孔隙对黑色页岩孔隙特征的贡献取决于 OM 含量、OM 类型和热成熟度。