Accumulation Characteristics and Enrichment Regularity of Tight Sandstone Gas Reservoirs in Zhongguai Area, Junggar Basin

As a kind of clean and efficient low-carbon energy, ight sandstone gas is of great significance to the transformation and upgrading of energy consumption structure and the realization of the goal of “carbon peaking and carbon neutrality”. The formation characteristics and enrichment laws of tight sandstone gas in the Permian Jiamuhe Formation in Zhongguai area, northwest margin of the Junggar basin, are unclear. Based on drilling, logging, 3D seismic, core and experimental analysis and testing data, the geological characteristics, enrichment laws and main controlling factors for high production of tight sandstone gas reservoirs in the study area are comprehensively analyzed. The research results show that the tight sandstone gas type of the Permian Jiamuhe Formation in Zhongguai area is mainly composed of oil type gas, coal type gas and mixed gas. The gas source is mainly from the source rock of Fengcheng Formation and Lower Wuerhe Formation in Shawan Sag. The source rock of the Jiamuhe Formation may supply hydrocarbon, which has the characteristics of multi-source hydrocarbon supply; The gas reservoir type is a lithologic stratigraphic trap type, with characteristics of distant source migration and multi-stage accumulation and accumulation; The dense reservoir is eroded by turbidite minerals and other minerals, forming relatively good physical properties in local areas as reservoir “sweet spots”. They are mainly distributed in the eastern part of the study area, and vertically, they mainly develop in the depths of 4320～4640 m and 4830～4900 m, with high yield layers mainly concentrated in the upper “sweet spots” zone. The enrichment and high production of tight sandstone gas reservoirs are controlled by the favorable diagenetic facies zones of reservoir “sweet spots” and locally developed paleo-uplift and structural fractures.