Research On Improved Algorithm Of Synchroextrating Transform And Its Application In Seismic Reservoir Identification

Time-frequency analysis is one of the common methods in the field of signal processing.Some T-F analysis methods,such as synchrosqueezing transformation and synchroextrating transformation are not accurate enough when calculating instantaneous frequency.To solve this problem,the amplitude and phase of the signal function are expanded by Taylor though the Taylor's approximation idea.The polynomial after expansion is put into the instantaneous frequency calculation formula and combined with SET,improving the precision of instantaneous frequency estimation formula of the SET,which solve the problem of SET in signal processing precision.By modifying the SET transform with different order Taylor expansion of amplitude and phase,the second-order synchroextrating transform(FSET2)and the high-order synchroextrating transform(FSETH)are derived.Finally,we study the application of two new algorithms in reservoir identification of seismic data.The main research contents and results of this paper are as follows:(1)Through the study of relevant literature on T-F analysis methods,we can insight into the methods such as short-time Fourier transform and SET transform,and the problems of these methods in signal processing,image processing,etc.;Through the research on the development history of T-F method,the improved idea of SET is obtained.It provides a supporting background for the following research.(2)The second-order synchroextrating transformation(FSET2)is proposed.The amplitude and phase of the signal are combined with the Taylor formula,and they are expressed by using the second-order Taylor expansion,and put into the instantaneous frequency expression.The new instantaneous frequency was used to calculate the second-order synchroextrating operator(FSEO2),and FSEO2 is applied to STFT spectrum to obtain the FSET2 spectrum.STFT,SET and FSET2 transform are used to test the single and multi-component simulation signal.The results show that: several methods can be used to characterize the time-frequency distribution of the signal,but FSET2 processes the time spectrum obtained by the signal to depict the signal with higher precision,which can provide more information for the follow-up research.(3)On the basis of FSET2 algorithm,the amplitude and phase of signal are expressed by the higher order Taylor expansion,and put them into the SET algorithms,with the help of a complex "operator" of time and frequency formulas,introduced the corresponding high order formula of instantaneous frequency estimation is deduced,and by using the delta function for high order synchronous extraction operator(FSEOH).A new FSETH time spectrum is obtained by combining FSEOH operator with STFT transform result.Different simulation signals are used to test the new method.From the time spectrum obtained by processing,it can be seen that FSETH is most accurate in describing the information of the lower frequency part and the information of the higher frequency part.(4)Research on new methods in seismic data processing.The STFT,SET,FSET2 and FSETH methods were used to analyze the simulated signals and the actual seismic data of the western Sichuan basin.From the processing results,it can be seen that the STFT has the roughest effect,and the time spectrum obtained by FSET2 and FSETH is better than that obtained by SET in terms of energy focusing.At the same time,the lateral continuity of constant frequency sections obtained by FSETH is better than that obtained by FSET2.