Basis tracking algorithm-based surface wave separation and suppression method

Abstract

The invention relates to a basis tracking algorithm-based surface wave separation and suppression method, which comprises the following steps of: adaptively establishing an overcomplete atomic library according to an actual frequency range of a seismic profile and structural characteristics of seismic signals, sparsely decomposing each seismic signal of the seismic profile through the basis tracking algorithm, and screening important atoms capable of approximately reestablishing the seismic signals; and adaptively setting an energy threshold and a main frequency threshold range according to the screened important atoms so as to find atoms forming a surface wave from the decomposed result of each seismic signal, and subtracting the seismic signals from surface wave components reestablished by the surface wave atoms to obtain the seismic signals after the surface wave is suppressed. The method has the characteristic of adaptively matching signals, and can reflect local characteristics of time domain and frequency domain of the seismic signals simultaneously; and compared with the one-dimensional Fourier transform filter surface wave suppression method, the method can effectively suppress the surface wave, and slightly damages an effective signal.

Description

technical field [0001] The invention relates to a surface wave base tracking algorithm separation and suppression method for suppressing surface wave interference of seismic data. Background technique [0002] Surface waves are the most coherent interference waves encountered in land seismic exploration. Its characteristics are: strong energy; low frequency, generally a few Hz to 30 Hz; low speed, which is 0.9 times the propagation velocity of the shear wave, and the apparent speed is generally 100 to 1000m / s, of which the apparent speed is 200 to 500m / s most common. The time-distance curve of the surface wave is a straight line. Due to the dispersion effect and absorption attenuation of the medium, the energy of the surface wave will rapidly attenuate with the increase of depth and propagation distance. At the same time, its frequency changes from high to low, forming a "broom shape", that is, dispersion occurs. In seismic data processing, the frequency difference and ve...

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Problems solved by technology

Although these methods have achieved a certain processing effect, there are still two deficiencies: ① After filtering, the seismic signal affected by surface wave interference is greatly different from the unaffected seismic signal energy

After this method was proposed, related applications appeared, such as signal denoising, feature recognition and medical image processing. Although some scholars have applied the basis tracking algorithm to seismic data denoising, most of them are to remove random noise. , very little is applied to the identification and extraction of surface waves

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