S-Transform Time-frequency Analysis Technology And Its Application Research In Seismic Prospecting

Fourier transform and inverse Fourier transform build up mapping for signal between time domain and frequency domain. Although Fourier transform can analyze signals in terms of time-domain or frequency-domain respectively, can not integrate with both directly. For non-stationary seismic signal, it is very important to understand frequency characteristic of different time around, so time-variant signals can be described using time-frequency joint denotation, then 1D time-domain signals can be mapped into 2D time-frequency profile, time-frequency joint characteristic of seismic signals can be expressed entirely. Because of the limitation of traditional time-frequency analysis methods, a newer time-frequency analysis method, S-transform is introduced into this paper.Traditional time-frequency analysis methods are summarized firstly in the paper, the definition, derivation and characteristic of S-transform are expatiated, 2D S-transform and generalized S-transform are introduced. S-tranform can be deduced from short-window Fourier transform or continuum wavelet transform and combine two kinds of time-frquency analysis methods advantage overcoming their disadvantage: S-transform has a direct relation with Fourier transform, the characteristics such as lossless invertibility, linearity, multi-resolution of wavelet. S-transform is a kind of linear time-frequency represent as short-time fourier transform and wavelet transform, so it has not cross-term ; S-transform has muti-resolution overcoming single resolution of short-time fourier transform. Otherwise, S-transform contains phase factor which wavelet transform has not. In order to understand the character of S-transform, theory models are designed, S-transform, short-time fouier transform and Wigner-Ville distributing are compared and analysised.Based on above theory, S-transform is firstly applied to some processing and interpretation of seismic prospecting.On the seismic processing, first-break picking is its first application due to high time-frequency resolution. different S/N ratios are added in theory seismic data, first-breaks are detected using S-transform, then which is applied to first-break picking of tomographic static in hilly data with lower S/N ratios; second, seismic surface wave has low frequency and regional property in time-frequency surface and S-transform has lossless invertibility. surface wave suppression technology based on S-transform is applied to theory data and practical data.On the seismic interpretation, the geological cyclothem bodies identification is its first...