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Inverting Near-Surface Absorption Bodies with Full-Waveform Inversion: a Case Study from the North Viking Graben in the
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
Summary
Shallow absorptive bodies are an ongoing challenge in velocity model building due to the dispersion and attenuation they cause to seismic data: ignoring absorption in model building can lead to erroneous velocities and poor imaging. Ray-tracing-based tomographic inversions for attenuation can perform well, but typically provide lower resolution than a full waveform approach. Also, the method carries inherent drawbacks in the near surface, where absorptive bodies are often at their most influential, due to acquisition limitations. This work highlights visco-acoustic full-waveform inversion (Q-FWI) as a method for estimating high-resolution velocity and attenuation models. We present a very large, real data, case study where Q-FWI has been applied to ~36,000 km2 of 3D, narrow azimuth, variable-depth streamer data over the North Viking Graben region of the Norwegian North Sea. The results delineate both known and previously unknown absorptive bodies of varying size and strength. Our results show that Q-FWI can invert for high-resolution velocity and attenuation models, providing superior imaging using an attenuation compensating pre-stack depth migration.
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