Near-offset extrapolation for free-surface multiple elimination in shallow marine environment

Abstract

The invention is a method for extrapolating missing near-offset seismic data () so that the data may be used, for example, in SRME or another multiple-reflection elimination method. The invention uses the reciprocity principle () to relate two seismic states (acoustic or elastic) that can occur in a time-invariant, bounded domain in space. One of these states represents the physical experiment for the acquisition of the actual seismic data where near-offset traces are missing, and the other state represents a synthetic experiment with no missing near offset traces, computer-generated on a much simpler earth model. The reciprocity relationship used to relate these two states is iteratively inverted for the missing near-offset traces (), preferably using only part of the synthetic data () so as to reduce inversion artifacts. The reference model acts as a constraint on the near-offset extrapolation.