가상 PP 반사파 영상 작성을 위한 비반사파 신호 및 공중점 범위에 관한 고찰

초록

To find major obstacles to the broad implementation of and to suggest effective processing methods for virtual PP reflection images using the first surface multiples, seismic data were synthesized and the characteristics of the virtual reflection data were analyzed. For the synthetic data for the two-layer horizontal model with a vertical boundary, seismic energy was assumed to be generated at five independent sources and their waveforms were computed at 99 receiver locations. Maximum amplitudes of reflection signals are less than 2% of those of the direct Rayleigh waves on an average. This indicates that the non-reflection seismic events should be suppressed before correlating traces for virtual seismic data with good signal-to-noise ratios. The stationary phase of virtual reflections should be considered in determination of the optimum common-midpoint (CMP) ranges for horizontal stacking. Additionally, the CMP ranges with large reflection amplitudes should be also considered for good signal-to-noise ratios of virtual stack images.

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