TECHNICAL DIFFICULTIES AND COUNTERMEASURES FOR GEOPHYSICAL RESEARCH IN JINZHOU 25-1 OILFIELD

A new approach for eliminating multiples is proposed in this paper. The approach is based upon the combination of the events realigning with the singular value decomposition (SVD) technology. The process of our approach to suppress multiples is as follows: (1) track reverberations via accurate ray tracing and divide the shot gather into different reasonable time windows according to the traced time-distance curves of reverberations. Within each time window, the multiple events are aligned to be horizontally flat. (2) filter out reverberations with SVD technology. (3) re-align the filtered data back to the original shot gather. Remove all reverberations tracked by ray tracing, and then, we can complete the multiple attenuation. Compared to conventional methods, our approach takes the mechanism of multiples into account adequately and requires no model. Further more, we can remove the multiples directly in shot gather without analyzing the velocity spectrum jumbled by multiples. The processing of synthetic and real examples clearly demonstrates the validity of the technology presented in this thesis.