f Seismic wave attenuation in layered porous rocks - theory and numerical experiments

Seismic wave attenuation derived from VSP and cross-borehole surveys is often treated as a prospective powerful tool of determining in site properties of hydrocarbon reservoir rocks. However, adequate and complete onderstanding of the seismic attenuation mechanisme in such rocks is not yet established. Attenuation coefficients observed at low frequencies usually do not agree with the predictions either of the classical Biot theory [1] (so-called global flow approach) or of the local fluid flow models [2]. Our approach to the problem is based on the idea (first proposed in [3] 1) that the discrepancy between measured and theoretically predicted attenuation might be related to the energy transfer from the ordinary elastic wave to the Biot's slow wave on the inhomogeneities. This effect is studied both theoretically and numerically.