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Theory and Modelling of Viscoelastic Anisotropic Media Using Fractional Time Derivative
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
Actual subsurface media can commonly behave not only the viscoelastic property due to the fluid-filled cracked rocks or porous sandstones, but the anisotropy characteristic results from periodic thin layers and preferred orientation cracks. Therefore, accurate seismic wave simulation requires to consider the stratum’s viscosity and anisotropy characteristics.
This paper presents a new viscoelastic anisotropic constitutive relation and the corresponding time domain wave equation based on the constant-Q model theory. The wave equation contain fractional order temporal derivatives which is the key to implement attenuation and unify viscoelastic and elastic cases into a set of linear equations. The advantages of our presented theory is that it possesses more unified, simple forms and more perfect constant-Q property than the viscoelastic anisotropic theory used in the past. Taking a 2D VTI media for example, a rotated staggered grid finite-difference scheme is used to numerically solve the equations with incorporating the convolutional perfectly matched layer (CPML) absorbing boundaries. The numerical simulation results show the feasibility and effectiveness of the theory.