Abstract：Frequency AVO analysis studies amplitude(energy) variation of target stratum versus frequency and offset after time-frequency transform of seismic data.It is difficult to identify tight thin gas reservoir on seismic data in time domain.In this paper,we introduce an approach for fluid identification on seismic data in frequency domain.Firstly,we start with rock physics analysis,and use statistic method to deduce the theory algorithm of AVO analysis in frequency domain for fluid identification based on velocity dispersion.Then,we do S transform to obtain more accurate data in frequency domain to analyze amplitude variation with frequency in reservoir on post-stack seismic data.In the end,we analyze amplitude variation with frequency and offset on seismic pre-stack data of reservoir.Applications of this method show that tuning effect of tight,thin sand with low porosity cannot cause abnormal frequency response in seismic frequency band,only frequency dispersion in high frequency band causes abnormal response.
