High-Resolution Velocity Update Using Full Waveform Inversion: A Case Study in East Breaks, Gulf of Mexico

摘要

In this case study located in East Breaks, Gulf of Mexico, we faced seismic imaging challenges caused by a mass-transport complex (MTC) below the seabed. The MTC is characterized by moderate-to-strong seismic velocity and amplitude variations due to both structural and stratigraphic inhomogeneities. Traditional tomographic velocity inversion methods could not provide sufficient resolution of the small-scale velocity anomalies within the MTC. As a result, seismic events below the MTC appeared distorted and out of focus. Multiple iterations of high-frequency full waveform inversion (FWI), up to 18 Hz, enabled us to derive a detailed velocity model of the MTC, thereby improving the seismic image beneath it. Detailed analysis at a deeper reservoir level showed that event continuity, gather flatness, AVO response and pre-stack P-impedance inversion were all improved after migration using the FWI-derived velocity.