Abstract: China's continental shale oil resource has great potential, and is an important alternative energy source for the petroleum industry. The First Member of Qingshankou Formation in the South of Songliao basin is rich in shale oil resources, and industrial and high-yield oil flows have been found in many wells through oil testing. Taking the Lower Part of the First Member of Qingshankou Formation as the research object, and the occurrence state of shale oil as the pointcut, this paper focuses on the quantitative evaluation of the amount of swelling oil, adsorbed oil, and free oil in shale oil enriched in high-quality lithofacies such as high organic matter lamellar shale and medium organic matter laminar shale, so as to reveal the occurrence characteristics of shale oil in underground shale reservoirs, and to provide guidance for further exploitation of shale oil in the South of Songliao basin. The shale oil is mainly stored in shale reservoirs in five states: Kerogen swelling state, kerogen adsorption state, organic pore free state, inorganic mineral adsorption state, and inorganic pore free state; Among them, the occurrence state of shale oil in high organic matter lamellar shale is mainly organic occurrence oil such as kerogen swelling oil, kerogen adsorption oil and organic pore free oil, and the organic occurrence oil amount can be as high as 253.0 mg/g TOC. The shale oil amount of well TY1 is the largest, followed by well CY8, and the amount of well H238 is the lowest; The occurrence state of shale oil in medium organic laminar shale is mainly inorganic occurrence oil such as inorganic adsorbed oil and inorganic pore free oil, up to 167.0 mg/g TOC. Well CY8 has the largest amount of shale oil, followed by well H258, and well H238 has the lowest amount of shale oil. Well TY1 and well CY8 are located in the semi deep-deep lake, where a large set of mud shale is developed, while well H238 is located in the outer front of the delta and closed to the source area, resulting in significantly lower shale oil accumulation than the wells in semi deep-deep lake. Therefore, the sedimentary environment is the main reason for the difference of shale oil accumulation in different areas.

Key words: Songliao basin, First Member of Qingshankou Formation, shale oil, occurrence state, quantitative evaluation