Measurement of ultrasonic bulk properties of water-saturated porous media

Acoustic signals are used extensively in the oil industry to determine the physical properties of reservoir rock. In the interpretation of these signals empirical laws play a major role. To obtain a more fundamental interpretation of the recorded wavetrains, the need for a comprehensive theory for wave propagation and attenuation in rocks is obvious. For this purpose, Blot's theory (1956) turned out to be a simple but effective two-phase theory. One fundamental feature of this theory is the existence of both a fast and 'a slow compressional wave, as well as a shear wave. Preliminary measurements of ultrasonic properties of water-saturated porous media, i.e. bulk attenuation and phase speed, show the predictive power of the Biot theory (Johnson, Plona and Kojima, 1994). In this paper we present new experimental data of bulk attenuation and phase speed for all three types of bulk waves, covering an ultrasonic frequency range from 100 kHz to 1 MHz. The results are compared with theoretical predictions of the Biot theory.