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Near Surface Characterization through Simultaneous Joint Inversion of Surface Waves and Refracted Waves
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 74th EAGE Conference and Exhibition incorporating EUROPEC 2012, Jun 2012, cp-293-00364
- ISBN: 978-90-73834-27-9
Abstract
Near-surface characterization is an important part of seismic data processing, especially for land data. Conventional approaches rely on refracted waves and use of inversion techniques to estimate compression-wave velocity models from the first-break traveltimes. However, in a complex geologic setting in the shallow part of the subsurface, velocity inversions and hidden layers may reduce the reliability of the refraction solution, even with high-quality first breaks. Surface-wave inversion techniques provide shear-wave velocity models that can be integrated in the near-surface characterization workflow. The VP and VS models inferred from first-break traveltimes and Rayleigh waves have several synergies. Their integration can provide an effective solution for challenging geological situations. A robust way of integrating the two methods is simultaneous joint inversion: within this inversion scheme, the two measurements, together with some geological and/or petrophysical relationships linking the subsurface properties, are used in the computation of a unique cost function, which is to be minimized. The solution of the inverse problem results in a multiproperty model fitting data of both measurements and the linking relationship. Different portions of the model are resolved by the interacting contributions of complementary measurements. A field example from Kuwait is discussed to demonstrate the method.