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An Attenuation Model from Dispersion Trends in North Sea Well Data
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
We observe and analyze systematic linear trends in check-shot drift from released well data from the Norwegian sector of the North Sea and relate this dispersion to seismic attenuation. We use reflectivity modelling at a well to assess that the contribution of scattering to attenuation is likely small. From the drift trends, we develop a regional model for the prediction of attenuation from P-wave velocity. This model is of a new form that acknowledges our observations of relatively low drift gradients (and hence low attenuation) at low velocities as well as at high velocities. We propose a tentative geological interpretation of the main features of the model in terms of porosity and fluid mobility. The model produces reasonable attenuation values at the high end of previously published values for a nearby area. The model has potential regional application in seismic processing and inversion and in the identification of zones of anomalous attenuation. The method for deriving the model should be applicable in other regions.