Adaptive Subtraction & Seperation For Surface-related Multiple Of Marine Seismic Data

Multiple elimination is always an important work in seismic data processing, especially in marine seismic survey. Multiple damages the quality of seismic data processing seriously. So it is significant to elimination all kinds of multiples effectively and reserve the primary possibly in seismic exploration.First, a review has been given for the multiple attenuation techniques. Then the author study the basic theory and procedures of prediction subtraction method based on wave equation and discuss the prediction and subtraction detailedly.The paper mainly studies the adaptive subtraction for surface-related multiple. Based on least squares principle, the single channel, multichannel, pseudomultichannel , expanded multichannel matching filter are formulated, resulting from second order statistic. The result is not satisfactory when primaries and multiples have overlap, so the adaptive subtraction based on high-order statistic is presented, which is based on independent component analysis.Matching filter methods were used in two model data and a real seismic data. The author analyze the results of several adaptive subtraction methods and demonstrate the advantages and weaknesses of various approaches. The result show that it is better to adopt pseudomultichannel and expanded multichannel least-square matching filter, especially when the multiple and the primary have overlap. The results also show that filter length, iterative number and matching channel affect multiples attenuation result . The method of independent component analysis is illustrated with model data and real seismic data. Results show that this method can separate multiple from original data .