WAVE-PROPAGATION IN THE EFFECTIVE MODEL OF ALTERNATING POROUS AND IMPERMEABLE SOLID LAYERS

Elastic properties of finely layered media are of great interest for s eismic exploration. Theoretical models give a dependence of overall pr operties on constituent parameters. On the one hand they help geophysi cists to estimate possible ranges of anisotropy and on the other hand they provide a basis for interpretation of measured anisotropic parame ters in terms of microstructure. Last forty years such models with ela stic constituents have been extensively used. Recently they have been updated for describing fractured rocks (Hsu and Schoenberg, 1993). in this case thin. and soft elastic layer models fracture. However reserv oir rocks are porous and permeable. Porosity and permeability are take n into account by well-known Blot model. Finely layered porous sequenc es have some distinctive properties which are the topic of modern rese arch (Schoenberg, 1996). Therefore it is important to update developed concepts to porous medium. Bakulin and Molotkov (1998, 1997) who gene ralized Backus averaging on poroelastic medium have done first step. H ere we pay attention to one special case when there is only one prefer ential direction of fluid flow in porous rock. This may be caused by p resence of impermeable barriers or lenses, which are modeled as set of solid layers intersecting porous medium. Such model corresponds to hi ghly hydraulically anisotropic rock, which has very strong anisotropy of pore space structure and permeability.