Abstract: The volcanic rocks of the Carboniferous Bashan Formation are widely developed in the Shazhang fault-fold belt in eastern Jungaer Basin, and the exploration and development of the carboniferous volcanic gas field in the adjacent Wucaiwan Sag indicates that the carboniferous volcanic rocks in the study area also have the potential of reservoir formation. To provide support for volcanic oil and gas exploration in this area, this paper comprehensively studies the characteristics of volcanic reservoirs and their influencing factors by using drilling, rock sample, the microscopic chip, imaging logging, analysis data. The results show that: 1) volcanic rock reservoir lithology of Bashan Formation is mainly composed of volcanic lava, fused volcanic breccia, pyroclastic rock, volcanic-sedimentary rock and sub-volcanic rock, which can be identified as eruptive facies, overflow facies, volcanic-sedimentary facies; 2) the main reservoir space is primary reservoir space (primary pores) and secondary reservoir space (secondary pores and fractures), and there are four types of reservoir space combination: pore + dissolved pores in almond body + fracture, pore + dissolution pore, dissolution pore + fracture and fracture; 3) the volcanic rock is of medium-low porosity and medium permeability reservoir with poor overall physical property and heteroqeneity; 4) the development of favorable volcanic reservoir in Bashan Formation is mainly controlled by lithology and lithofacies, weathering and leaching, and tectonic fragmentation.

Key words: volcanic rock reservoir, reservoir characteristics, influencing factors, Shazhang fault-fold belt, Bashan Formation