The successful hydraulic fracturing test of shale oil in the second Member of the Liushagang Formation from the Weixinan depression of the Beibuwan basin has opened the prelude to offshore shale oil exploration and research. However, the lack of research data on offshore shale oil, coupled with unclear reservoir development characteristics and difficulty in identifying sweet spots, necessitates further investigation. This study focuses on characterizing the shale reservoir of the second Member of the Liushagang Formation in the Weixinan depression. To comprehensively assess this reservoir, we employed a innoative approach, combining high- precision core analysis techniques with high- resolution logging technology. This allowed us to evaluate both reservoir quality and completion quality parameters, including brittleness index and in- situ stress, ultimately aiding in the identification of potential sweet spots within the Formation. The results show a diverse mineralogy dominated by clay, quartz, and calcite, and the dominant lithofacies is mud- rich siliceous shale, mixed siliceous shale, and argillaceous siliceous shale. The TOC content is relatively high, averaging 4.5%, indicating a strong hydrocarbon generation potential. Both the effective porosity and movable fluid porosity of the shale oil reservoirs are high, averaging 8% and 4.0%, respectively. However, the pore structure exhibits significant heterogeneity. Taking advantage of high- resolution image logging data and core data, open fractures and sealed fractures were developed in the shale oil reservoir. Furthermore, the shale oil reservoir is characterized by high oil saturation, with an average effective oil saturation of 60%. Confocal laser scanning experiments demonstrate that light hydrocarbons mainly exist in bedding fractures, while heavier hydrocarbons are stored in the organic residue. Importantly, the middle section of the second Member of the Liushagang Formation exhibits a high brittleness index and relatively horizontal stress difference. This suggests a favorable environment for the formation of complex fracture networks during hydraulic fracturing, enhancing completion quality. By integrating reservoir quality and completion quality data, we have successfully delineated promising target sections in the Liushagang Formation. This research provides a valuable theoretical basis for the exploration and development of shale oil resources in the second Member of the Liushagang Formation within the Weixinan sag of the Beibu Gulf basin.