Scientific Investigations Report 2007-5264
 
Abstract
Monopole and dipole logging data at the Mallik 5L-38, Mackenzie Delta, Canada, provide a challenge for sonic velocity and attenuation models used to remotely estimate pore-space gas hydrate content. Velocity and attenuation are linked, with velocity dispersion causing increased attenuation. Sonic waveforms for Mallik 5L-38, however, show no velocity dispersion in gas hydrate-bearing layers, yet are highly attenuated. Attenuation models applied to Mallik 5L-38 data are shown to be inconsistent with the observed velocity measurements, and therefore are suspect in their ability to predict gas hydrate content. A model explicitly linking velocity and attenuation data is presented, accurately predicting gas hydrate content from velocity data alone while demonstrating that the attenuation mechanisms at the Mallik 5L-38 site have not yet been identified. |
Version 1.0 Posted December 2007 |
Lee, Myung W., 2007, Velocities and attenuations of gas hydrate-bearing sediments: U.S. Gelogical Survey Scientific Investigations Report 2007–5264, 11p.
Abstract
Introduction
Acknowledgments
Theory of Three-Phase Equation
Derivation of equation
Moduli of dry frame
Computation of moduli formed by grain and gas hydrate
Dissipation potential
Velocity and Attenuation Modeling
Real Data Example
Discussion
Velocity
Estimation of gas hydrate amounts using velocity
Attenuation
Comparison with other theories
Conclusions
References
| Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Acrobat Reader or similar software is required to view it. Download the latest version of Acrobat Reader, free of charge or go to access.adobe.com for free tools that allow visually impaired users to read PDF files. |
