Abstract: [Objective]Despite depths exceeding 8000 meters, it still retains high-quality reservoir and exhibits prolific production of industrial gas flow in Bozi area of Kuqa Depression. However, there are obvious differences in the physical properties plane of the tight sandstone reservoirs of the Bashijiqike Formation. In order to clarify the development characteristics of such reservoirs and reduce the risks associated with deep-ultra-deep oil and gas exploration. [Methods]Based on the experimental analyses of well logging, thin section petrography, high pressure mercury injection and PVT phase diagrams, the characteristics of tight sandstone reservoirs and the causes of physical property differences were discussed. [Results] The rock types of Bashijiqike Formation reservoir in Bozi area which the study highlights are medium-fine grained lithic feldspar sandstone and feldspar lithic sandstone. Notable differences exist in the spatial distribution of carbonate cement content. Original porosity in the medium-fine sandstone reservoirs that ranges from 32.4% to 38.1%, exhibiting comparable intergranular compaction strength primarily reliant on point-line contacts. Southern reservoirs maintain an average porosity of 8.6% and an average permeability of 3.4 mD. Central reservoirs present an average porosity of 6.53% and an average permeability of 0.65mD. The average porosity and permeability of the northern reservoir are 4.9% and 0.62mD respectively. Primary intergranular pores dominate the southern reservoir space, whereas residual intergranular pores and dissolution porosity prevail in the northern and central zones. Furthermore, superior pore-throat structures characterize the southern region compared to the northern and central sectors. [Conclusion] The physical properties of sandstone reservoirs in Bozi area are controlled by sedimentation, diagenesis and tectonic processes (fissures), among which carbonate cementation emerging as the principal factor of the late reservoir physical properties alterations. Overpressure, hydrocarbon fluid charging, and fracture development significantly affect carbonate cementation, subsequently causing variations in reservoir physical properties. Stronger overpressure, earlier oil and gas charging time and limited fracture filling result in better reservoir properties in southern Bozi than those in northern and central areas.
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