PROBLEMS OF SEISMIC RESEARCH ON HETEROGENEOUS GEOLOGICAL MEDIA

Abstract

Some general problems of seismic studies of heterogeneous geological media (HGM) are discussed. Two types of HGM are studied: thin-layered periodical media and porous saturated media. The parameters determining the properties of the HGM components (grains, layers, fluids) are called local. The Riznichenko (1949b)—Postma (1955) theory, the Frenkel (1944)—Biot (1956) theory, and the theory of elastic spheroidal packing are used to estimate the relationships between the integral parameters of HGM (seismic velocities, seismic absorption coefficients, etc.) and the local HGM parameters. An analysis of these relationships is given on the basis of mathematical modelling. Several cases of integral parameters reaching beyond the range of changes of local elastic parameters (extra-high and extra-low values) are described. The applied aspects of seismic study of HGM are discussed: the evaluation of the local Poisson's ratio in thin-layered media, and the evaluation of the type of fluid in porous rocks. The theoretical results are compared with experimental ones.