Serving as the primary stratigraphic target for lacustrine shale oil exploration, the second member of the Lucaogou Formation in the southeastern Junggar Basin exhibits highly complex lithofacies resulting from multi-source sediment inputs. This member is predominantly composed of mature- to high-mature, organic-rich shales containing Type II1 kerogen. Hydrocarbon generation potential increases toward the depocenter, peaking in organic-rich laminated felsic-rich shales (LF1) owing to localized enrichment of Type I kerogen. However, despite its exceptional hydrocarbon generation capacity, fluid mobility in LF1 is severely restricted by pronounced kerogen swelling and rapid compaction-induced closure associated with its extremely fine-grained texture. Conversely, reservoir quality progressively deteriorates from terrigenous sources toward the depocenter. Organic-rich laminated argillaceous-calcareous mixed shales (LF4) emerge as the optimal reservoir lithofacies. In LF4, relatively coarse grains provide a rigid framework that resists compaction, thereby preserving primary felsic intergranular pores while minimizing the effects of kerogen swelling. Within the transitional facies, reservoir quality is notably reduced: organic-rich laminated carbonate-bearing argillaceous felsic shales (LF3) suffer from compaction-induced pore loss and partial kerogen blockage, whereas organic-rich laminated clay-bearing calcareous felsic shales (LF2) undergo carbonate cementation that occludes primary pores, resulting in high capillary resistance and strong fluid binding. LF1 exhibits the poorest reservoir quality, being strongly affected by both compaction and kerogen swelling. Comprehensive analyses reveal that pore complexity is fundamentally controlled by lithofacies heterogeneity, which governs oil retention and fluid mobility. Ultimately, this study identifies LF4 as the most favorable lithofacies for shale oil exploration in the southeastern Junggar Basin, while also highlighting the reservoir stimulation potential of other shale lithofacies.