N-th root slant stack for enhancing weak seismic signals

Seismic imaging of complicated underground structures with severe surface undulation (i.e., double complex areas) is challenging owing to the difficulty of collecting the very weak reflected signal. Enhancing the weak signal is difficult even with state-of-the-art multi-domain and multidimensional prestack denoising techniques. This paper presents a time–space dip analysis of offset vector tile (OVT) domain data based on the τ-p transform. The proposed N-th root slant stack method enhances the signal in a three-dimensional τ-p domain by establishing a zero-offset time-dip seismic attribute trace and calculating the coherence values of a given data sub-volume (i.e., inline, crossline, time), which are then used to recalculate the data. After sorting, the new data provide a solid foundation for obtaining the optimal N value of the N-th root slant stack, which is used to enhance a weak signal. The proposed method was applied to denoising low signal-to-noise ratio (SNR) data from Western China. The optimal N value was determined for improving the SNR in deep strata, and the weak seismic signal was enhanced. The results showed that the proposed method effectively suppressed noise in low-SNR data.