Seismic Attenuation from VSP and Well Log Data: Approaches, Problems and Relative Contribution of Scattering
R. Pevzner, T. Muller, R. Galvin, A. Alasbali, M. Urosevic and B. Gurevich
Event name: EAGE Workshop on Seismic Attenuation
Session: Estimation from Field Data: Borehole Seismic
Publication date: 28 October 2013
Info: Extended abstract, PDF ( 1.84Mb )
Price: € 20
All methods for quantitative interpretation of seismic data are based on the analysis of amplitudes of seismic (reflected) waves. Seismic attenuation along the ray path of a wave significantly affects this amplitude information. As such, understanding of this phenomenon has a huge impact for the industry. For the last sixty years vertical seismic profiling (VSP) was an obvious method of choice for exploring this phenomenon in-situ. A large number of different approaches for attenuation estimation were introduced. We have tested a large number of these methods and developed a reasonably robust workflow for attenuation estimation based on the modified centroid frequency shift method. Seismic attenuation measured from seismic data (so-called apparent attenuation) comprises two different components, namely, transfer of the energy into heat (absorption) and scattering. We employ seismic modelling using finely-layered model of the medium obtained from the log data as a part of the workflow to estimate relative contribution of scattering. In order to investigate causes and mechanisms of seismic attenuation we select ~70 wells from several areas in Australia (primarily from NW Shelf) with publically-available high-quality well log, VSP data and geological information. In this presentation we show some preliminary results from this study.