Research And Application Of Time-Frequency Analysis Method In Seismic Data Processing

In the oil and gas exploration,due to the complexity of the underground geological structure,the current seismic acquisition technology may lead to the mixed phenomenon of effective seismic signals and noise interference,which will have a certain impact on the later data processing.In order to obtain accurate and effective seismic signals and achieve fine reservoir characterization,seismic data denoising and time-frequency seismic signal identification methods are indispensable,which plays an extremely important role in the later interpretation of data and reservoir prediction.Therefore,the joint analysis of seismic signals in the time domain and frequency domain by time-frequency analysis method not only can effectively remove noise interference,but also can more accurately describe the instantaneous amplitude,instantaneous frequency,and other information of time-varying seismic signals.Important structural and lithologic characteristics of the strata.Current common time-frequency analysis methods mainly include Short Time Fourier Transform(STFT),Wavelet Transform(WT),S Transform(ST)and Generalized S Transform(GST).These time-frequency analysis methods can only give overall changes in the time domain and frequency domain,and cannot intuitively see the distribution of local frequency components,and cannot simultaneously take into account both time resolution and frequency resolution,and the calculation formula is complicated,and you need to select the basis function in advance.The Hilbert-Huang Transform(HHT)can generate instantaneous frequency properties with local characteristics to facilitate observation of local frequency transformations.Its formula is relatively simple,avoiding the situation that the product of time window and frequency window is constant,time and frequency can achieve higher resolution at the same time.This paper mainly studies and compares several common time-frequency analysis methods with Hilbert yellow transform,analyzes the superiority of Hilbert's yellow transform method,and applies it to actual seismic data processing for verification.First,from the traditional methods of time-frequency analysis,the principles of several common time-frequency analysis methods are introduced,including Fourier transform(FT),short-time Fourier transform(STFT),wavelet transform(WT),and S transform.Generalized S transform,and the derivation relationship between these methods,analyzes the advantages and disadvantages of these time-frequency methods.Then the Hilbert-Huang transform(HHT)is introduced and the EMD decomposition in the Hilbert-Huang transform is improved.The CEEMD method is introduced to eliminate the "modal aliasing" phenomenon existing in the EMD decomposition.Then apply the CEEMD-based HHT method to theoretical models and actual seismic data processing.The results show that the denoising effect of the CEEMD method in actual seismic data is better than the EMD method,and the modal aliasing in the EMD decomposition can be well eliminated.problem.The transient amplitude profile after denoising by the CEEMD method has better continuity in the horizon,is clearer,and has a higher signal-to-noise ratio.Compared with other time-frequency analysis methods,the Hilbert-Huang Transform method based on CEEMD can better reflect the local variation characteristics of the single-frequency profile,and the singlefrequency profile has better stratum continuity.