In order to make further use of the advantages of the seismic data in the characterization of the sandbody changes among the wells, the technical studies on the seismic sedimentology are conducted for Layer S m in Lama- dian Oilfield under the condition of dense well pattern. The results show that after processing of the seismic phase shift, the correspondences between the reservoir sandbodies with the obvious contrast of the wave impedance and seismic reflection characteristics are much better; with the help of the phase-shift seismic data, the distribution of the channel sandbodies with thickness more than 5m can be directly predicted; the isochronie stratal slicings can very well reveal the vertical sedimentary characteristics of the reservoirs, thus the ability to identify the sandbody edges can be greatly improved, so the sedimentology has become the effective approach for the reservoir prediction in the density well pattern.