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

摘要

The invention is a method for extrapolating missing near-offset seismic data (101) so that the data may be used, for example, in SRME or another multiple-reflection elimination method. The invention uses the reciprocity principle (102) 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 (103), preferably using only part of the synthetic data (102) so as to reduce inversion artifacts. The reference model acts as a constraint on the near-offset extrapolation.

主权项

1. A computer-implemented method for estimating missing near-offset traces in measured seismic data, comprising relating all or part of synthetic seismic data, generated using a reference subsurface model, to the measured seismic data by a reciprocity relationship, and then iteratively inverting the reciprocity relationship for the missing near-offset traces using a programmed computer, followed by using the estimated missing near-offset traces to augment the measured seismic data, then applying a technique for removal of multiple reflections, then interpreting the seismic data with multiple reflections removed for indications of accumulations of hydrocarbons, and in the event of such an indication at a location, drilling a well at the location and producing hydrocarbons.