Evaluating seismic imaging methods on reservoir interpretation

Abstract

The improvement of seismic migration techniques plays a crucial role in the exploration of reservoirs with complex geological structures (e.g. complex structures under-salt, mountainous structures) and complex formation (such as VTI and HTI fractured reservoirs). However, it is unclear whether these imaging methods are beneficial for reservoirs with complex geological structures and relatively complicated sedimentary processes. In order to study this issue, a 2D model with scatter points in monocline structures is established. Based on this model, image gathers of the scatters and seismic attributes (amplitude, waveform, frequency and phase) obtained based on four different migration methods are compared. Our study shows that the structure precision of common shot prestack depth migration (PreSDM) is the greatest, Kirchhoff PreSDM is greater than Kirchhoff prestack time migration (PreSTM), and poststack migration (NMO+PostMig) is the lowest. In addition, investigated from the perspective of seismic interpretation of inner reservoirs, the wave equation common shot PreSDM is the most effective method, followed by NMO+PostMig, Kirchhoff PreSDM and finally Kirchhoff PreSTM. The non-continuous wave field continuation manner in Kirchhoff PreSTM and PreSDM decreases the spatial continuity of its seismic attributes, which affects interpretations of the inner reservoir.