Abstract: In view of the burial characteristics of exploration targets, complex surface and geological conditions in steep slope zone of southern Biyang sag, the problems such as the structural fragment, large fault plane dip angle in the basinal boundary and lateral lithology variation near the fault belt occurred during previous seismic exploration are analyzed, and corresponding methods for them are proposed. In order to solve these problems, the technicians responsible for data acquisition and processing as well as interpretation are cooperated together in line with the guide of geologic model to optimize observation system by computer modeling, select a reasonable shot depth by microlog and refraction data, and bury geophones by drilling hole in piedmont zone. For data processing, the prestack depth migration profile is used to make the imaging of boundary large fault planes distinct and their locations reliable, including that the minor fault points and the interlayer contacts are clear, so that it is convenient for geologists to make a precise interpretation.

Key words: Biyang sag, structure, seismic interpretation, prestack migration, forward modeling