The Research Of Harmonic Noise Rejection Based On Slip-sweep Acquisition Method

The harmonic interference exists in the data acquired from seismic exploration with vibroseis. In conventional seismic exploration, the harmonic interference can be removed when the data is correlated, and seismic data will not be affected by harmonic noise. But with the development of the seismic data collection methods, the slip sweep exploration method became one of the most important exploration methods. It can improve the exploration efficiency and cut the cost. Also this method has been used in many geophysical companies. With this new exploration method, the harmonic interference can not be removed by correlation, so we need to findnew technology to eliminate the harmonic noise.In this paper, we sum up the characteristic of slip sweep data though analyzing the raw data. Based on this, phase-shift filter (PPSF) is used. The method only requires the computation of a purely deterministic phase-shift filter that has the phase spectrum of a hypothetical kth harmonic distortion. It can eliminate the harmonic noise through changing the phase of the raw data and deal nothing with the amplitude. So,I can get true amplitude data at the same time. In this paper, the phase-shift filter is improved which takes fundamental harmonic as the factor of the filter and separates the harmonic noise from harmonically distorted sweep (HDS).In the process of computer simulation, an emulational HDS signal which contains 4 orders harmonic noises is designed. The 1st harmonic is used as ppsf filter. In the experiment, the harmonic noise can be clearly separate from harmonically distorted sweep (HDS). Then we conduct calculation using real data. In accordance with the data's characteristic feature, the reference sweep signal is chose from the auxiliary channels and the improved ppsf filter is obtained. After that, we separate the harmonic noise and fundamental harmonic from the harmonically distorted sweep (HDS) by improved ppsf filter. The improved ppsf filter has to be applied in the slip sweep seismic data, so we do some improvement and choose suitable mode for processing. Through all of the improvement, the harmonic noise can be removed from harmonically distorted sweep (HDS) which is acquired from the slip sweep seismic exploration. This method can not only get the accurate processing data but also promote the processing efficiency.