Abstract:The seismic signal received by sensors is very weak because the energy is absorbed and attenuated by subsurface and deep layer during signal propagating. The high frequency component was much more seriously absorbed and attenuated than low frequency component. The key issues for high density seismic acquisition are to receive and identify low reflection coefficient or high frequency weak signal. In this paper, the relationship of weak signal to subsurface, dominant frequency, offset and deep target layer was analyzed based on a typical elastic-viscoelastic earth model. The results show that it is very difficult to give expression to the advantages of broad band frequency in high density seismic acquisition in the area with strong subsurface attenuation and low S/N ratio due to the existence of the cut off frequency. Good condition excitation can improve weak signal energy and give more contribution to broaden frequency band. The effective reflection coefficient can be better presented in small and middle receiver-source offset and can be well extracted.
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