Abstract: In view of the extremely strong heterogeneity, complex pore structure, significant productivity difference between wells and unclear reservoir quality difference mechanism of tight sandstone reservoir, the quality difference mechanism of tight sandstone reservoir controlled by lithofacies was discussed according to comprehensive core and logging data by taking the tight sandstone reservoir in the Member 8 of the lower Shihezi Formation in southern Sulige Gasfield. It is found in the study that the results show that the reservoir quality was controlled by lithofacies by affecting the diagenetic evolution sequence, and the reservoir quality of the fine conglomerate - pebbled coarse sandstone facies was the best, followed by that of the coarse sandstone facies, with a permeability greater than 1.00 mD, and mainly developed with intergranular pores - necked throats;according to the content of lithofacies and plastic debris, the diagenetic evolution sequence of reservoirs was classified by four categories: coarse lithofacies (collective term of fine conglomerate - pebbled coarse sandstone facies and coarse sandstone facies), medium sandstone facies rich in rigid particles, medium sandstone facies rich in plastic particles, and fine sandstone facies;after experienced diagenetic sequence of weak compaction, strong cementation and strong dissolution, the coarse lithofacies had the best physical properties, and were mostly distributed as isolated lenses in sand in striped distributary channel. This distribution feature is the main reason for the obvious difference in productivity between wells. The study results provide a theoretical basis and guidance for the prediction of high-quality reservoirs and the exploration and development of tight sandstone gas reservoirs.

Key words: tight sandstone, tight gas, lithofacies, reservoir quality, diagenesis, Sulige Gasfield