Success and opportunities of advanced full-waveform inversion on ocean bottom seismic data

Abstract

The latest full-waveform inversion (FWI) developments and their application on ocean bottom seismic (OBS) field data sets are discussed in this paper. Geological complexity including shallow gas absorption, strong azimuthal anisotropy and substantial velocity heterogeneity can result in severe subsurface imaging degradation which hinders hydrocarbon exploration. OBS is a preferred acquisition solution to improve sub-surface imaging and provide new insight for exploration in complex environments. FWI is the natural choice for velocity updates using OBS data. To maximize the value of OBS data, new developments of advanced FWI algorithms have been implemented to tackle different geological challenges. Viscoacoustic time-lag FWI (Q-FWI) has been developed to address gas absorption issues. Orthorhombic time-lag FWI (ORT-FWI) has also been implemented to tackle strong azimuthal anisotropy. We demonstrate how the OBS acquisition and advanced FWI algorithms together produce a high-resolution velocity model that effectively solves the imaging challenges and enhances the exploration potential in several real data examples.