In recent years, major breakthroughs in shale oil exploration have been achieved in the Ganchaigou area of the Qaidam Basin, highlighting the significance of investigating the lithofacies and reservoir characteristics of the plateau saline lacustrine basin for sweet spot identification. Focusing on shale oil reservoirs in the Ganchaigou area, we identify the lithofacies types and systematically examine the differences in the reservoir and oil-bearing properties of shales with varying lithofacies. Furthermore, we determine dominant lithofacies and primary factors controlling the reservoir formation. The methods employed in this study include core and thin section identification, whole-rock mineralogy and in-situ trace-element distribution testing, large-field splicing scanning electron microscopy (MAPS), high pressure mercury injection (HPMI) and nitrogen adsorption experiments, along with one-dimensional nuclear magnetic resonance (NMR) measurements. The results indicate that the reservoirs in the study area exhibit four lithofacies: massive limy dolomite (carbonate mineral content: above 70 %), laminated limy dolomite (carbonate mineral content: 50 %-70 %), lamellar mixed siliciclastic-carbonate rock (carbonate mineral content: 10 %-50 %), and mixed siliciclastic-carbonate rock with intermittent horizontal beddings (carbonate mineral content: 10 %-50 %). The massive and laminated limy dolomites, among others, exhibit the predominance of intercrystalline pores, large reservoir spaces with high connectivity, and pores with large oil saturation index (OSI), thus serving as dominant lithofacies; The lamellar mixed siliciclastic-carbonate rock manifest poorly developed matrix pores but high permeability due to intensively developed laminae; The mixed siliciclastic-carbonate rock with intermittent horizontal beddings, lacking pores and fractures, display poor reservoir properties. The reservoir formation process of the dominant lithofacies is governed by three factors: (1) carbonate fabrics, which determine the degree of macropore development; (2) the contents of terrigenous felsic fine-grained sediments and clay minerals, which dictate the specific surface adsorptivity; and (3) the developmental degree of laminae, which can ultimately enhance the reservoir permeability.

Oil generation in the continental shale has laid the resource foundation for the originality and development of China’s petroleum industry; continental shale oil production is blazing a new trail in this field. In this paper, based on the geological conditions of continental shale oil in China, it is found that the main types of shale oil generally have four basic geological characteristics, which are large-scale continuous distribution, the domination of inorganic pores, the enrichment of "sweet areas" , and initial production that is controlled by relatively high organic maturity and high yield that is governed by relatively high formation pressure. Then, as examples for the geological characteristics and development practice of continental shale oil, four key areas of Longdong, Gulong, Jimsar, and Jiyang are systematically summarized. Finally, the future prospects of continental shale oil in China are put forward. Middle-high maturity shale oil is currently the main force of development, and middle-low maturity shale oil also has a considerable development prospect after technological improvement. Meanwhile, "sweet area/spot sections" assessment and technological innovation are still research areas to be improved.