New threshold function seismic data de-noising method based on wavelet transform

A technology of wavelet transform and seismic data, applied in the field of oil and gas seismic exploration, can solve the problems that affect the approximation degree of reconstructed signal and real signal, limited denoising effect of time-varying signal, large signal distortion, etc.

Inactive Publication Date: 2018-02-16
SOUTHWEST PETROLEUM UNIV
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Problems solved by technology

However, these two threshold functions still have defects: when using hard threshold denoising, because the function is discontinuous, the reconstructed signal will oscillate, and many artificial noise points will be generated at the edge of the image
However, when this method reduces the wavelet coefficient with a large absolute value, there is always a constant deviation, which directly affects the approximation between the reconstructed signal and the real signal, resulting in a certain loss of high-frequency information, which will lead to blurred edges of the image
In practical applications, using soft threshold to denoise the signal is relatively smooth, but there is a large signal distortion, and using hard threshold to denoise the effect is not ideal, and the denoising effect on time-varying signals is limited

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  • New threshold function seismic data de-noising method based on wavelet transform
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  • New threshold function seismic data de-noising method based on wavelet transform

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Embodiment Construction

[0029] In order to improve the quality of seismic data in areas with low signal-to-noise ratio, the noise and effective signals are separated to achieve pre-stack denoising of seismic data. This method is used to denoise seismic data.

[0030] First, for the noisy signal f i (t) Do wavelet transform to get wavelet coefficient W j,k , input the noisy signal gather f i (t), then find the variance σ i (t), find the adaptive weighted superposition s(t), where,

[0031] n indicates that the selected adaptive window starts from the nth channel, m is the window length, i indicates the i-th channel, and t indicates the time t, and iteratively calculates the adaptive variance σ point by point i,new (t), where σ i,new (t)=[f i (t)-s(t)] 2 , and then judge whether σ i,new (t)-σ i-1,new (t)i,new (t) replace the original variance σ i (t) Perform data processing again, if yes, then substitute the adaptive variance into the calculation threshold λ, Create a new threshold functi...

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Abstract

The invention provides a new threshold function seismic data de-noising method based on wavelet transform. The method addresses the problem that the quality of seismic data in a low signal-to-noiseratio region of oil and gas seismic exploration cannot meet the requirements of treatment and interpretation. By establishing a new threshold function overcoming the defects of hard and soft thresholds and using wavelet transform as a core idea, the de-noising goal of seismic data is gained, and a new threshold function is determined. Compared with the current similar technologies, the method hasthe advantages that the de-noising result is closer to original useful signals and the quality of the seismic data is greatly improved.

Description

technical field [0001] The method of the invention belongs to the field of oil and gas seismic exploration, and relates to the design and application of seismic data denoising methods, and the method is effective for oil and natural gas seismic exploration in all regions. technical background [0002] The complex high and steep structural areas in piedmont rich in oil and gas resources have become the focus of current seismic exploration. With the refinement of exploration, noise interference is often very serious in areas with complex structures and low signal-to-noise ratio. If pre-stack records Without denoising processing, it will lead to unclear horizons or unreal structures on the final stacked section, making the quality of seismic data not meet the processing requirements, thus restricting the further improvement of seismic exploration in this area. [0003] The purpose of denoising seismic data is to suppress the noise on the original record as much as possible, but...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V1/36
CPCG01V1/364G01V2210/324
Inventor 罗仁泽代月李阳阳赵万明罗翔宇
Owner SOUTHWEST PETROLEUM UNIV
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