Velocity and attenuation of linear waves in porous media saturated with gas and its hydrate

One of the main methods of searching for gas hydrate deposits is seismic exploration and acoustic logging. For correct processing and interpretation of measurement data, it is necessary to know the acoustic properties of hydrate-containing rocks, which can be studied on the basis of laboratory experiments and adequate mathematical models. In this paper wave propagation in a hydrate-containing porous medium is investigated. The skeleton is considered to consist of grains cemented with gas hydrate, and is modeled by a homogeneous solid phase with effective parameters. The elastic moduli of the composite skeleton of a porous medium are calculated from the elastic moduli of the grain material and hydrate using a well-known method. The velocities and attenuation coefficients of linear waves are calculated within the framework of a two-velocity model of a porous medium. The calculated data are compared with the experimental data of other authors on sound velocities in hydrate-containing porous samples. The influence of the properties of the base rock, the saturating fluid, and hydrate saturation on the propagation of linear waves is studied.