Theoretical analysis and numerical simulation of acoustic waves in gas hydrate-bearing sediments  

作　　者：Lin Liu Xiu-Mei Zhang Xiu-Ming Wang 刘琳;张秀梅;王秀明(State Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100149,China;Beijing Engineering Research Center of Sea Deep Drilling and Exploration,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]State Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100149,China [3]Beijing Engineering Research Center of Sea Deep Drilling and Exploration,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Chinese Physics B》2021年第2期344-354,共11页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11974018 and 11734017);the Strategic Pilot and Technology Special Fund of the Chinese Academy of Sciences,China(Grant No.XDA14020303)。

摘　　要：Based on Carcione-Leclaire model,the time-splitting high-order staggered-grid finite-difference algorithm is proposed and constructed for understanding wave propagation mechanisms in gas hydrate-bearing sediments.Three compressional waves and two shear waves,as well as their energy distributions are investigated in detail.In particular,the influences of the friction coefficient between solid grains and gas hydrate and the viscosity of pore fluid on wave propagation are analyzed.The results show that our proposed numerical simulation algorithm proposed in this paper can effectively solve the problem of stiffness in the velocity-stress equations and suppress the grid dispersion,resulting in higher accuracy compared with the result of the Fourier pseudospectral method used by Carcione.The excitation mechanisms of the five wave modes are clearly revealed by the results of simulations.Besides,it is pointed that,the wave diffusion of the second kind of compressional and shear waves is influenced by the friction coefficient between solid grains and gas hydrate,while the diffusion of the third compressional wave is controlled by the fluid viscosity.Finally,two fluid-solid(gas-hydrate formation)models are constructed to study the mode conversion of various waves.The results show that the reflection,transmission,and transformation of various waves occur on the interface,forming a very complicated wave field,and the energy distribution of various converted waves in different phases is different.It is demonstrated from our studies that,the unconventional waves,such as the second and third kinds of compressional waves may be converted into conventional waves on an interface.These propagation mechanisms provide a concrete wave attenuation explanation in inhomogeneous media.

关 键 词：gas hydrate-bearing sediments Carcione-Leclaire model time-splitting staggered-grid finite-difference slow-wave characteristics 

分 类 号：O429[理学—声学]