Estimation of viscoelastic attenuation of real seismic data by use of ray tracing software: Application to the detection of gas hydrates and free gas |
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| Authors: | Fateh Bouchaala Claude Guennou |
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| Institution: | 1. UMR 6538, domaines oceaniques, IUEM, université de Brest, place N.-Copernic, 29280 Plouzané, France;2. Institute of Geophysics, Czech Academy of Science, Bocni II 1401, Praha 4, 14100, Czech Republic |
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| Abstract: | Analysis of P wave velocity profiles and seismic data recorded over the 2002 Hydratech cruise conducted in the Storegga region, North of Norway, has shown the existence of anomalies (a velocity decrease) in some layers of the medium. An elastic propagation model is not sufficient to explain clearly these anomalies, since the viscoelastic attenuation, represented by the quality factor QP, is sensitive to physical phenomena of geological media. The combination of the quality factor profile with the velocity profile leads to realistic explanations of these anomalies. In this article, we explain the procedure which we developed for determining the QP profile from the P wave velocity profile and the seismic data recorded during Hydratech cruise. Both the QP and velocity profiles indicate anomalies in the same layers. Based on previous studies, we interpret that these anomalies are being due to existence of gas hydrates and free gas within these layers. |
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| Keywords: | Viscoelasic attenuation Gas hydrates Free gas Ray tracing |
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