Elastic full-waveform inversion of a targeted FWI OBN survey at Atlantis field

Atlantis field in the Gulf of America has seen substantial improvements in seismic image fidelity in recent years, due largely to the combination of modern OBN acquisition and advances in full-waveform inversion (FWI). However, there remain areas at Atlantis — especially beneath the highly complicated salt overburden — where the image quality is still deficient, which presents a challenge when interpreting in such areas. This characterization applies to conventional migration images as well as FWI velocities and derived reflectivity volumes. To help address this limitation, we designed and executed a targeted long-offset OBN acquisition specifically aimed at increasing diving-wave illumination at a key subsalt region of interest, and we used elastic FWI to jointly invert these data together with fullfield OBN data. Results demonstrate that, with this approach, we are able to more accurately resolve the velocity model and derived reflectivity image in the targeted area, validating the original acquisition design concept.