Abstract: The geopetal structures of volcanic rocks in Beisantai field of Junggar basin are similar to those of carbonate rocks, which are mainly found in volcanic gas pores and autoclase fissures. The bottom of them is dominated by filter mud deposit, the top of them by crystal sodalite and other authigenic minerals, with flat interface. The discovery of volcanic geopetal structures is of important significance in identification of top and bottom of volcanic rocks, classification of lithologic facies and oil-gas exploration. It is concluded that the strata developed with geopetal structures have relatively premium quality, developed solution porosity, higher production rate as oil zone and oil-water bearing zone.

Key words: Junggar basin, volcanic rock, geopetal structure, andesite