Abstract:Random noise attenuation technique developed in recent years is obvi-ously effective on improving the signal-noise ratio of surface seismicstack section(or stack migration section).This technique is used on the premise that at each frequency,thesignals which have been converted from time-space domain into frequency-space domain can be expressed as the sum of complex exponential func-tions which are independent of wavelet waveform.In other words,suchsignals at each frequency may be considered as a linear event.This pro-perty can be used to separate signal from noise.All the upgoing,down-going and converted shear wave events in VSP data show such a linearproperty,which,therefore,offers a prerequisite for us touse,the techni-que.The experimemental result proves that the application of the random noise attenuation technique to VSP data processing obviously improvessignal-noise ratio and first break pickup.