Abstract: A large potential for oil and gas exploration and development is found at the Feixianguan Formation in the Qilibei-Duokouhe area of the northeastern Sichuan Basin, but the high-frequency rotary seismic identification and tracking are difficult, the multi-stage beach body is vertically stacked, and the reservoir has strong lateral non-homogeneity, so a supporting staged seismic prediction method for the migratory oolitic beach reservoir has not been formed. In response to the difficulties of the high-frequency rotary seismic identification and tracking and the staged seismic prediction of oolitic beach reservoirs, the horizontal fine tracking of internal cycles in the Fixianguan Formation was carried out on the basis of the method of zoning different seismic reflection phase zones, to make a fine prediction of multi-stage oolitic beach reservoirs in the Fixianguan Formation. The study shows that the seismic reflection interface tracking and comparison method for the sequence stratum based on different seismic reflection phases can effectively solve the problem of identifying the interface of high-frequency stratigraphic sequences, and the Fixianguan Formation has been divided into five types of seismic reflection phases: biaxial strong reflection, internal weak reflection, uniaxial strong reflection, cluttered-subparallel reflection, and multiaxial strong reflection; the results of the qualitative prediction of amplitude- and arc length-sensitive attributes and the quantitative prediction of the neural network inversion make clear that the high-quality reservoirs mainly develop in the The results of the quantitative prediction using amplitude and arc length sensitive attributes and neural network inversion showed that the high-quality reservoirs are mainly developed in the Cycle Ⅱ, and from the Cycle Ⅱ to the Cycle Ⅲ, and the reservoirs have the pattern of migrating and accumulating from the east to the west, and from the plateau to the trough. The practice has shown that the seismic reflection interface tracking and comparison method for the sequence stratum of different seismic reflection phases, combined with the reservoir prediction method controlled by sensitive attributes, is suitable for the migratory oolitic beach reservoir. This study is also useful for the fine reservoir prediction in the same type of gas reservoirs.

Key words: high-frequency stratigraphic sequence, oolitic beach prediction, Feixianguan Formation, Sichuan Basin