Soluble organic matter (SOM) in shale can be divided into free and adsorbed states. However, the characteristics and occurrence mode of different types of SOM remain unclear, which are of great significance to the unconventional oil and gas and hydrocarbon generation mechanism. This paper investigates the characteristics of different types of SOM, discusses the relationships between SOM and minerals, and clarifies the occurrence mode of SOM in shale. Twenty shale samples collected from the Dongying Sag were successively subjected to “organic solvent extraction - alkali hydrolysis - hydrochloric (HCl) acid hydrolysis - hydrochloric/hydrofluoric (HCl/HF) acid hydrolysis” treatments to obtain different types of SOM (extracted SOM, alkali-hydrolyzed SOM, HCl acid-hydrolyzed SOM and HF acid-hydrolyzed SOM), which were then separated into different group components by column chromatography. X-ray diffraction (XRD) and Diffuse reflectance infrared Fourier transform (DRIFT) were used to analyze the original samples and treated residues. Comparison of organic characteristics reveals: (1) Comparison of SOM content shows the order of extracted SOM (about 80%) > HF acid-hydrolyzed SOM (10%) > alkali-hydrolyzed SOM (7%) > HCl acid-hydrolyzed SOM (3%). (2) The extracted SOM is mainly composed of saturates (average content of 65.22%). Resins are the main components of the alkali-hydrolyzed SOM (38.28%) and HCl acid-hydrolyzed SOM (43.69%). For the HF acid-hydrolyzed SOM, the content of asphaltenes is the highest (76.52%). (3) Comparison of SOM polarity shows the order of HF acid-hydrolyzed SOM > alkali-hydrolyzed SOM > HCl acid-hydrolyzed SOM > extracted SOM. Based on the organic characteristics and the relationships between SOM and minerals, there are three occurrence modes of SOM in shale: (1) Free SOM in pores (extracted SOM) is free in the pores and physically adsorbed on pore surfaces. (2) Mineral-bound SOM (alkali-hydrolyzed SOM and HCl acid-hydrolyzed SOM) is chemically adsorbed onto the surfaces of clay minerals and carbonates, and is enclosed in the recrystallized carbonates. (3) SOM in inaccessible kerogen (HF acid-hydrolyzed SOM) is retained by inaccessible kerogen. These findings fully demonstrate the differences in the characteristics of SOM in different occurrence states, which are exemplified by the content, composition, polarity and adsorption. These differences provide a new insight for the study of unconventional oil and gas and hydrocarbon generation mechanism.

页岩中的可溶性有机质（SOM）可分为游离态和吸附态。但不同类型SOM的特征及赋存方式仍不清楚，这对非常规油气及生烃机制具有重要意义。本文研究了不同类型SOM的特征，探讨了SOM与矿物的关系，阐明了SOM在页岩中的赋存模式。对东营凹陷采集的20个页岩样品依次进行“有机溶剂萃取-碱解-盐酸(HCl)酸解-盐酸/氢氟酸(HCl/HF)酸解”处理得到不同类型的SOM(萃取SOM、碱-水解的 SOM、HCl 酸水解的 SOM 和 HF 酸水解的 SOM)，然后通过柱色谱将其分离成不同的组成分。X 射线衍射 (XRD) 和漫反射红外傅里叶变换 (DRIFT) 用于分析原始样品和处理后的残留物。有机物特性比较表明：（1）SOM含量比较显示，提取的SOM（约80%）>HF酸解SOM（10%）>碱解SOM（7%）>HCl酸解SOM（ 3%）。(2) 提取的SOM主要由饱和物组成（平均含量为65.22%）。树脂是碱解 SOM (38.28%) 和 HCl 酸解 SOM (43.69%) 的主要成分。对于 HF 酸水解的 SOM，沥青质的含量最高（76.52%）。(3) SOM极性比较显示HF酸解SOM>碱解SOM> HCl 酸水解的 SOM > 提取的 SOM。根据有机质特征以及 SOM 与矿物的关系，页岩中 SOM 的赋存方式有 3 种： (1) 孔隙中游离 SOM（提取的 SOM）游离于孔隙中，物理吸附在孔隙表面。(2) 矿物结合型SOM（碱解SOM和HCl酸解SOM）化学吸附在粘土矿物和碳酸盐的表面，被重结晶碳酸盐包裹。(3) 难接近的干酪根中的SOM（HF酸水解SOM）被难接近的干酪根截留。这些发现充分说明了SOM在不同发生状态下的特征差异，具体体现在含量、组成、极性和吸附等方面。