Prestack Seismic FVO Analysis Based On S Transform

The dynamic features of amplitude, frequency and phase can be changed during the propagation of seismic waves, and these changes can be used to characterize reservoir geological information of underground strata. The prestack seismic gathers not only preserved the information of the seismic records versus offset, but also retained a large amount of shear wave information, which could provide a richer and more accurate basis for lithology identification and fluid exploration. The research on the prestack seismic attribution of the reservoir has become one of the hot spots in the reservoir fluid detection area.The development of time-frequency analysis makes it possible to study the spectrum information of the seismic records accurately. The S transform is a variable resolution time-frequency analysis method, and it maintains the direct relationship with the Fourier transform, and can directly correspond to the frequency. In the high frequency section, the time resolution is high, while the frequency resolution is high in the low frequency section. Using S transform to analyze seismic data, it can nicely fulfill the requirements of the seismic data analysis.Based on the phenomenon of the frequency versus offset after seismic wave propagating throughout the fluid containing, and influence of formation of seismic frequency response, the thesis carries out the research on the FVO(Frequency Versus Offset) analysis methods based on prestack seismic gathers. FVO analysis method includes FVO forward modeling method and FVO reservoir inversion method. FVO forward modeling method uses the different reservoir lithology FVO response of the model to set up corresponding FVO detection criterion; FVO reservoir inversion methods to estimate the seismic parameters of rock formations and to describe the oil and gas reservoir through FVO response in the actual earthquake records extracting by S transform.In this thesis, the author uses three layers parallel model as the forward model to obtain the FVO detection criterion of gas reservoir and water reservoir; S transform is used to extract partial angle stack of prestack seismic frequency attenuation gradient, and the extracted data is used to as reservoir prediction combined with FVO detection criterion of different fluid. The effectiveness of FVO analysis method is verified by theoretical verification and practical data.