Optimised Spectral Merge of the Background Model in Seismic Inversion

Seismic inversion generates low-frequency modulations if the frequency content of the background model does not merge smoothly into the spectrum of the inverted seismic data. An incorrect low-frequency phase is another source of inversion artefacts. We present a systematic method of selecting a background model and low-frequency phase response that minimises the misfit at the spectral merge. The method compares well-log and seismic relative impedances computed at best-match well-tie locations over a range of background models and low-frequency phase corrections. The background models are specified by a low-cut corner frequency and the phase corrections by the phase intercept at zero frequency. The method is illustrated by application to broad-band inversion.