Research On Denoising Method Based On Wavefield Continuation

The focus of exploration in China has gradually shifted from the eastern gentle area to the western complex area.The western region has unique landform characteristics and complicated underground geological structure.These two factors cause serious noise development in actual seismic records,which greatly reduces the SNR of seismic data.How to improve the signal-to-noise ratio of seismic data and ensure the reliability of seismic data interpretation has become the most critical issue in this stage of work.Conventional denoising methods separate effective signals and noises according to the difference between noise and effective waves in a certain domain.But all of the conventional denoising methods have the problem of strong pertinence and loss of effective wave energy.Therefore,it is of great significance to proposes denoising methods of more effective.Most of the noise in seismic data is caused by near surface factors.The focus of this study is to use the method of continuation of the wave equation to filter all the noise related to the near surface in the seismic data.This paper first deduces the basic formula of the continuation of the wave equation,introduces the conventional denoising method of the wave equation,and proposes the denoising method based on continuation of the wave equation.Then the phase shift method is used to compile the program.Through the establishment of model,the simulation data is processed,the results are compared and analyzed,and the influence mechanism of each parameter in the continuation denoising method is studied.After that,by establishing a model and adding different kinds of noise,the applicability of the denoising methods in this paper on various types of noise is studied.Finally,the actual data is processed and the results are compared to verify the actual effect of the continuation denoising methods.Specifically,the following research work has been done:1)Describe the theory of wave field continuation,and derive the basic formula of wave equation continuation;2)Study the general wave equation denoising method;3)Introduce the principle based on phase-shift method and the continuation denoising method,as well as the formula used in program implementation;4)Denoise the model data,compare the denoising results by changing the parameters,and study the effect of each parameter on the denoising results;5)Through establishing the model and using trial model data,verify the applicability of the continuation denoising method for various types of noise;6)Handle the actual seismic data,compare and analyze the processing results,and verify the effectiveness of the continuation denoising method.Through research,we can find:1)Continuation denoising method has obvious denoising effect,and can remove most of the noise caused by shallow surface factors;2)The two parameters including background speed and continuation depth determine the actual effect of continuation denoising,while the continuation step length affects the processing accuracy and computational efficiency.3)Continuation denoising has no obvious denoising effect on random noise.In the actual processing,a random noise denoising module needs to be added.