Improvement of inverse dispersion technique for ground roll attenuation in sedimentary environment

Abstract

Ground roll, often characterized as high energy, low velocity, low frequency and dispersion, which always dominates a large part of shot records and damages the desired reflections. The attenuation of ground roll is important for high data resolution and signal to noise ratio (S/N) in seismic processing. Conventional frequency-wave number (F-K) filter is effective in eliminating linear noise, but they do not deal well with appearance linear noise, like dispersive fan-shape ground roll. In the F-K domain, the components of ground roll and the desired reflection always overlap, which leads to destruction of the low-frequency components during the F-K filtering process. A novel inverse dispersion method is introduced to overcome this disadvantage. The proposed method transforms dispersive ground roll towards non-dispersive, high velocity linear noise. The time delay caused by dispersion is calculated and compensated by using an inverse dispersion operator. Then the ground roll is separated from the desired reflections and can be easily subtracted by the F-K filter. The conventional f-k filter can efficiently attenuate the ground roll without affecting the desired data, thus improve the resolution and S/N of seismic data. Model test and real data application demonstrate the feasibility and efficiency of the proposed method in ground roll attenuation.