Spectral Decomposition And Coherency Attributes Analysis Based On Second-Order Synchrosqueezing Generalized S-Transform

With the development of oil and gas exploration in China,unconventional oil and gas resources such as fractured and lithologic oil and gas reservoirs have gradually become the main targets of the exploration.These reservoirs have put forward higher requirements for the accuracy of the seismic exploration.As one of the popular methods to get effective information in seismic data,time-frequency analysis method plays an important role in seismic interpretation.Due to the low resolution of traditional time-frequency analysis methods,it is difficult to meet the accuracy requirements of complex oil and gas reservoirs.Therefore,it is urgent to develop a high-resolution time-frequency analysis method.The synchrosqueezing method is one of the effective method to improve the resolution of traditional time-frequency analysis methods.This method squeezes the energy of the time-frequency spectrum along the frequency axis to obtain the high-resolution effect,so it is widely used.In this paper,based on the existing synchrosqueezing theory,we obtained a new high-precision time-frequency analysis method named the second-order synchrosqueezing generalized S-transform.This article first analyzes the basic principles of the generalized S-transform,expounds the cause of the energy divergence phenomenon of the generalized S-transform,and puts forward the specific ideas of the synchrosqueezing generalized S-transform to solve this problem.Then,in order to solve the problems of inaccurate calculation of instantaneous frequency and low precision of the synchrosqueezing generalized S-transform,we combined the second-order synchrosqueezing method which has more complete basic assumptions with the generalized Stransform,and obtained the second-order synchrosqueezing generalized S-transform.Through the simulation signal test,the second-order synchrosqueezing generalized S-transform can improve the resolution of the time-frequency spectrum.Compared with the generalized S-transform and the synchrosqueezing generalized S-transform,the time-frequency spectrum is more accurate and the noise resistance is stronger.In order to further verify the advantages of the second-order synchrosqueezing generalized S-transform,the spectral decomposition experiment and coherency attribute analysis experiment based on this proposed method are carried out on 3D model data and real seismic data respectively,and the results are compared with those of the conventional generalized S-transform and the synchrosqueezing generalized S-transform.The results show that the spectral decomposition profile based on the second-order synchrosqueezing generalized Stransform has higher resolution and stronger noise resistance,so it is conducive to the accurate interpretation of thin layers and faults.In addition,in the characterization of small faults,the coherency attributes based on the second-order synchrosqueezing generalized S-transform can provide more intuitive and real information for the identification of small faults.The second-order synchrosqueezing generalized S-transform proposed in this paper can improve the resolution and accuracy of seismic interpretation,so it has important guiding significance for improving the success rate of oil and gas exploration.