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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• 作者：Fateh Bouchaala^a ; ^b ; ^{fbouchaala@ig.cas.cz} ; Claude Guennou^b ; ^{guennou@univ-brest.fr}
• 关键词：Viscoelasic attenuation ; Gas hydrates ; Free gas ; Ray tracing
• 刊名：Comptes Rendus Geoscience
• 出版年：2012
• 期刊代码：87_16310713
• 类别：ear
• 出版时间：February, 2012
• 卷：344
• 期：2
• 页码：57-66
• 文件大小：916 K

摘要

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 Q_P, 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 Q_P profile from the P wave velocity profile and the seismic data recorded during Hydratech cruise. Both the Q_P 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.