Target-oriented Elastic Full Wave Form Inversion

A method for full wave form elastic inversion is presented. The method works target-oriented, by which we mean that the surface data is redatumed to the top of an objective sequence of appr. 500 m thickness, containing a reservoir with top and bottom seals. The method accounts for all internal multiple scattering and transmission effects over the target interval, making the data model, in terms of the subsurface properties, non-linear. The method has been tested on realistic synthetic data with noise, created with an exact metod (Kennett) from real well-logs, using a locally 1.5D model. The results are very good, recovering the elastic parameters very well on a 3 m grid, with spatial bandwidth beyond what could have been expected from the temporal seismic bandwidth, projected onto the wave number scale with the help of the mean velocity. Density is well predicted over the seimic bandwidth, but not outside. The actual redatuming aspect of the method has not been tested yet, because the synthetic data were generated directly at the top of the objective interval.