Seismic Data Normalization And Interpolation Based On Fourier Transform

Due to the surface conditions(such as rives, lakes and valleys) and barriers(such as roads and bridges),The position of geophones is usually irregular in real data acquisition of seismic prospecting. In addition, bad coupling effect, environment disturbance or instrument factors will generate some useless traces and shots, which need to be removed in the processing procedure. In marine seismic prospecting, cables deviate from designed position because of feathering. With the in-depth development of seismic prospecting, the acquired data becomes larger and larger. On one hand we hope to get dense sampled data in order to obtain more accurate subsurface structure. On the other hand, in consideration of cost, data should be sampled sparsely in special direction. In consequence, the data we obtain is usually sparse and irregular.In subsequent processing steps, sparsely and irregularly sampled data will bring in noise, as well as influence some multi-traces processing technique, such as stacking, wave equation migration, multiple removal and time-lapse seismic. Therefore, reconstruction of seismic data is very crucial and necessary. The work in this paper includes two parts, namely normalization and interpolation, both can be called reconstruction. However, in the first case, the trace position is totally different from real sampling position, we designed another observing system in the work region. The trace number after regularization can be equal with original irregular sampled trace number, or can be larger or smaller than it. In the second case, the data after regularization contain all the original acquisition traces, we just interpolate the missing traces. The trace number after regularization must be larger than original irregular sampled trace number.In the normalization of seismic data, Antileakage Fourier Transform is studied and a improvement approach is promoted. After a simple processing technique on Nonuniform Discrete Fourier Transform(NDFT) in Antileakage Fourier Transform’s procedure, we use Nonuniform Fast Fourier Transform(NFFT) to dramatically improve computational efficiency. The effectiveness of Antileakage Fourier Transform combined with NFFT is proved through synthesis model experiments.In the interpolation of seismic data, we studied two interpolation methods, namely Projection Onto Convex Sets(POCS) and Iterative Thresholding(ITH). An improvement to ITH is proposed to obtain better interpolation result. The new technique uses linear interpolation to get more accurate spatial frequency spectrum. The effect of Iteration Thresholding combined with Linear Interpolation is proved to be better than POCS and ITH in seismic data interpolation.In this paper, seismic data regularization and interpolation are both be carried out in FX domain to partial frequency components. Compared with implemented in TX domain, the computational amount is greatly reduced and the accuracy of reconstruction can also be improved.