A NMO Correction Method Without Stretching Distortion

Abstract

The conventional NMO correction method usually causes stretching distortion, especially in shallow layer and at large offset. This paper analyzed the reasons of stretching distortion and calculated the possible revising range of NMO correction values. Then corresponding updated NMO correction values can be obtained by adding the conventional NMO correction value to a series of equal-spaced correction values within the revising range. NMO correction without stretching distortion would be realized with the best NMO correction value chosen from all the updated values using cross-correlation method. Here we set the near-offset stacked trace after conventional NMO correction as a standard trace in the choosing of NMO updated correction value. Then selected a time window centering on each time sample and carried out NMO correction using each updated NMO correction value respectively, and calculated the cross-correlation of the data in the time window and that in standard trace, so the best NMO correction value is the updated one which corresponding to the largest cross-correlation value. The method can achieve NMO correction without stretching distortion in the case of crossing events in seismic data and has strong practicability. We proved its accuracy and effectiveness by model and practical data processing.