Poro-acoustoelastic constants based on Pade approximation

“

The conventional acoustoelasticity encounters problems of divergence in describing stress-induced velocity variations and limitless elastic wave velocities for higher effective stresses. The key to these problems lies in the elastic constants that have been changed indirectly by higher effective stresses, but are still treated as unchanged in computation. In general, loading stress enhances strain energy, causing an increase of elastic wave velocities. On the other hand, stress loading could induce frame-related attenuation and therefore decrease the original stiffness of porous rocks, which makes the elastic constants decrease quickly. The resulting elastic wave velocities are limited, especially for higher effective stresses.

”