Low-frequency deceleration of a filtration wave in layered-inhomogeneous permeable formations

Analytical frequency dependences of the absorption coefficient, wavenumber, and phase velocity were constructed for filtration-wave fields in a highly permeable interlayer bounded from above and from below by layers having high permeability in the vertical direction. It is shown that as the frequency decreases, the phase velocity of the wave decreases to values below this velocity in the porous medium, and low-frequency deceleration occurs.