Abstract: The volcanic rock types, characteristics of lithofacies, pores, and fractures are further analyzed and studied by means of core observation, identification of common slice and casting slice under the microscope, rock chemical analysis and high-speed mercury penetration. The factors influencing reservoirs are analyzed from the perspectives of diagenesis, lithology, and lithofacies. Volcanic rocks in the studied area can be classified into two major categories, i.e., volcanic lava and pyroclastic rocks, of which the lithophysa rhyolite, pellets rhyolite and ignimbrite are favorable reservoirs. Lithofacies can be divided into 5 facies and 16 subfacies. The upper subfacies and the top subfacies of eruptive facies as well as the hot debris flow subfacies of explosive facies are favorable reservoir facies. In addition, the pattern of volcanic lithofacies and the law of facies evolution of the studied area are proposed in this paper.

Key words: volcanic rock type, lithofacies, characteristics of pore structure, reservoir