Trigger time synchronization in shallow seismic exploration

Abstract

An algorithm to synchronize the trigger time in reflection shallow seismic data is developed. Trigger time delay and shot statics (hereafter together referred to as the shot distortion) are handled simultaneously. The approach is to estimate the shot distortion on each common shot gather (CSG) and then to eliminate the distortion by shifting all the traces in that CSG. Relative shot distortion between two consecutive CSG's is estimated by computing the average of the time shifts of maximum cross-correlations between the first reflections on the corresponding traces in the two CSG's. The CSG number 1 is used as the datum on which shot distortion is estimated using receivers nearby shot location 1. The shot distortion on each CSG is then calculated by relative shot distortion compared to CSG 1. Traces in all the CSG's are then shifted to eliminate the shot distortion, thus synchronizing the trigger times. Testing against field data shows that alignment in common receiver gathers can be greatly improved, therefore supporting the validity of this algorithm.