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Waveform Inversion of Sparsely Sampled Data over a Shallow Gas Area
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Presence of gas clouds in the overburden can be challenging for imaging as it creates velocity anomalies leading to severe multi-scattering effects. Waveform inversion has proven to be a good alternative for velocity estimation in complex media. In the context of shallow gas anomalies, we show that largely decimated datasets can be used to improve the velocity model. We apply 3D acoustic waveform inversion to a strongly decimated 3D narrow-azimuth streamer data to improve imaging below the gas. Although the decimation of the input data was quite drastic, using a structural smoothing filter allow us to reconstruct a fairly detailed P-wave velocity model of the subsurface. The resulting velocity model gives improved imaging and shows a better correlation between image and model.