Seismic dispersion and the relation between static and dynamic stiffness of shales

The main focus of this work is on the characterization of the static and dynamic elastic properties of overburden shales by laboratory experiments; some of the studies were additionally conducted on sandstones. The work was carried out using a specially designed low frequency apparatus at SINTEF's Formation Physics Laboratory. The apparatus allows for measurement of dynamic elastic rock properties at seismic and ultrasonic frequencies as well as measurements of quasi-static mechanical parameters. The technique also provides a possibility for full anisotropy characterization with transversely isotropic rocks (shales). One of the main experimental achievements of the present work was the development of a novel method for direct P-wave modulus measurements at seismic frequency. This new and unique method allows for significantly more accurate measurements of seismic dispersion of anisotropic rocks, in particular shales.