Abstract:For the research on the characteristics and main controlling factors of volcanic rock reservoirs, core observation, casting thin section identification, physical property testing and logging data analysis were utilized to conduct the study on the characteristics, distribution and main controlling factors of the Carboniferous volcanic rock reservoirs in the Junggar Basin. The results showed that in the Chepaizi uplift, the Carboniferous volcanic rock reservoirs mainly developed volcanic effusion facies, explosive facies, tuffaceous facies and volcanic sedimentary facies, and the lithologies were mainly andesite, basalt, volcanic breccia, tuff and tuffaceous sandstone. The reservoir spaces were classified into connected pore type, fracture type, fracture-pore type and pore-cavity-fracture type according to the configuration relationship between pores and fractures. Affected by lithology and lithofacies, weathering and leaching effects and tectonic actions, the reservoir properties had strong heterogeneity. The dominant reservoir lithologies were andesite, volcanic breccia and tuff. A three-layer weathering crust structure composed of clay layer, hydrolysis layer and weathering and leaching layer was developed at the top of the Carboniferous, which significantly improved the reservoir physical properties. Fractures were an effective supplementary factor for reservoir development. Different from the previous studies that mainly focused on characterizing the characteristics of the dominant volcanic rock reservoirs, based on the coupled controlling effects of lithology and lithofacies, weathering and leaching, and strike-slip faults on the reservoirs, it was innovatively recognized that two dominant volcanic rock reservoir development models, namely fault-block body and fault-fracture body, were mainly developed in the study area. The research results have certain guiding significance for the exploitation of the Carboniferous oil and gas resources from east to west in the Chepaizi uplift.