Abstract: The Mesozoic volcanic rocks are the major reservoirs for the deep-buried gas in Songliao Basin. Comprehensive study shows that the formation of high-quality reservoir of Mesozoic volcanic rocks in Songliao Basin is controlled by lithology, lithofacies, fracture and diagenesis. The top of the flood facies, fracture-developed acidic explosive facies are the major development area of high-quality reservoirs. The volcanic lithology which controls the growth of pore is thought as the basis for the formation of high-quality reservoirs. The comparative studies on physical properties of different volcanic lithology indicate the acidic volcanic rocks are preponderant type of reservoir rocks. Awhole and independent volcanic edifice is composed of volcanic conduit facies, flood facies, explosive facies, extrusive facies and volcano sedimentary facies from core to edge. Acomparative analysis illustrates that the volcanic lithofacies control distribution of high-quality reservoirs in independent volcanic edifice and explosive facies and the top of flood facies around volcanic crater are favorable zone for reservoirs. Deep fractures, which not only betterment filtering conditions of seepage flow, but also impel growth of secondary pores, are important pathways for deep fluids, and key factors for buildup of gas pool with high production. Besides, the highangle fractures densely developed are easy to form favorable reservoir zones with the assemblage of high-angle fractures and dissolution pores. Based on above conclusion, there are 272 volcanic edifices comprehensively identified in whole basin on the basis of seismic data and so on, with first class of 127, second class of 96 and third class of 49, which provided the basis for exploration deployment.

Key words: Songliao Basin, Mesozoic volcanic rocks, controlling factors of reservoirs, distribution prediction