Abstract: The exploration and development of Chinese terrestrial shale oil has made significant progress and has become an important field for expanding oil and gas reserves and boosting crude oil production in the petroleum industry.To investigate the development characteristics and formation mechanisms of continental shale lithology and reservoir pore. The main research objects are the mixed shale of the Lower ES3 Submember in the Bonan Subsag of Jiyang Sag and the E1f2 Member in the Gaoyou Sag of the Subei Basin, as well as the matrix shale of the Dongyuemiao Member and Liang2 Member in the Fuxing area of the Sichuan Basin. Based on the observation and description of rock cores, various experimental testing techniques such as whole rock mineral X-ray diffraction, thin section, micro area XRF, high-pressure mercury injection low-temperature nitrogen adsorption joint measurement, micro CT, argon ion polishing scanning electron microscopy, and overburden porosity were used to comprehensively characterize and compare the lithofacies and reservoir pores of continental shale, and to explore the influencing factors and formation mechanisms of reservoir pores. The research results indicate that: Continental shale develops multi-component and multi-scale sedimentary structures, which are controlled by the alternating input of terrestrial and endogenous sources. The sedimentary structure combination types and lithofacies types of mixed shale are more abundant and diverse than those of matrix shale. Bonan is mainly composed of bedded-laminated carbonate mixed shale, bedded felsic mixed shale, laminated carbonate shale, and massive carbonate shale. Gaoyou is mainly composed of laminated felsic mixed shale, laminated carbonate shale, bedded felsic shale, and massive clay mixed shale. Fuxing is mainly composed of massive clay shale, laminated shell carbonate shale, or laminated felsic shale; Based on the differences in pore carriers, a pore division scheme for continental shale oil reservoirs was established, proposing that various inorganic minerals and organic matter components in continental shale can form pores, with carbonate minerals and clay minerals being the most favorable pore forming carriers. Bonan is mainly composed of carbonate mineral pores, Gaoyou is mainly composed of carbonate mineral pores and felsic mineral pores, and Fuxing is mainly composed of clay mineral pores and carbonate mineral pores; High quality lithofacies is the foundation of pore development, and differences in mineral composition, structure, and sedimentary structures can all affect the quality of pore development. Massive clay (mixed) shale and laminated carbonate (mixed) shale have better pore development, while laminated (bedded) felsic (mixed) shale has average pore development, and massive carbonate (mixed) shale has poor pore development; The type and evolutionary sequence of diagenesis are key factors in controlling the formation and preservation of reservoir pores. Rigid mineral particles are stacked in layers or locally mixed to form anti compaction support structures, which are beneficial for pore preservation. Clay mineral transformation and carbonate mineral dissolution are commonly developed pore increasing processes. The inorganic pores of the Bonan and Gaoyou mixed shale are mainly controlled by compaction, recrystallization, and dissolution, and there is basically no development of organic matter pores; The inorganic pores of the Fuxing matrix shale are controlled by compaction, clay mineral transformation, and shell calcite dissolution, while organic matter pores are developed in the asphaltene.

Key words: Continental shale oil, Shale reservoir, Pore type, Inorganic pore, Bonan Sag, Gaoyou Sag, Fuxing Region