Study On Denoise Technology Of Shallow Seismic Reflection Data

Ground roll is a regular noise wave existing widely in shallow seismic reflection data, having low frequency, low velocity and other characteristics. Because of strong energy, Ground roll often dominates in shallow seismic reflection records. It is because of the existence of ground roll which is normally found in the shallow reflection data, seriously affecting the reflection data signal to noise ratio. It can bring a lot of inconvenience and trouble to follow-up processing of the reflection data. So suppression of ground roll is very necessary for reflection data. In order to suppress surface waves and protect the effective signal and provide a reliable data of the high signal to noise ratio, to find a more ideal way is imperative.Rayleigh wave is sort of sub-wave, which is low frequency, low velocity, it's suppression methods are based on the characteristics of these. Firstly, the frequency filter is applied in shallow reflection data processing, application effect is observed. Because one-dimensional filter can not meet the requirements of two-dimensional data processing, the introduction of two-dimensional Fourier transform. two-dimensional seismic data will be transformed into the frequency - wavenumber domain. FK filter will be designed to suppress the opposite waves, and use the two-dimensional discrete wavelet transform to seismic data transformation time, space, frequency, wave number of four-dimensional domain. Using a variety of methods to process wavelet coefficients, through the decomposition and reconstruction, obtained the shallow reflection data after the suppression of ground roll. Verified by actual data, This methods achieved certain results.In order to overcome shortcomings of the traditional ground roll suppression methods, this article introduces one-dimensional continuous wavelet transform, each single-trace seismic data transformation to the time - scale domain for processing. The coefficients of regional which ground roll domain are attenuated and then reconstructed, obtained the shallow reflection data after the suppression of ground roll. Comparing with FK filter and others, the results show that the method can effectively suppress the ground roll. In order to use the relationship between traces, the paper also introduces a "standard trace" concept. Within scale normalization at each time, the positioning time of ground roll interference, by attenuation of the wavelet coefficients at interference time, after reconstruction of the wavelet coefficients obtained the suppression of ground roll record of seismic data. The results show that the attenuation of ground roll interference at the same time, also can keep the reflected wave. Measured by the whole line of single shot data processing, the effect of stack section obtained show that this method provides an effective way for suppression of ground roll.