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Physical Properties |
Postgraduate Research Institute for Sedimentology, University of Reading, Whiteknights, Reading RG6 2AB, UK
A laboratory technique for the measurement of compressional and shear wave velocities and attenuations (quality factors) of sedimentary rocks at pressures up to 70 MPa and at frequencies up to 1 MHz was published by Winkler and Plona in 1982. In the method the rock sample is enclosed between buffer rods. The arrival times and amplitudes of the signals reflected from its top and base are compared. A similar technique has been used for many years in the non-destructive testing of metals and plastics. This paper describes the use of a single-frequency pulsed sine wave for the velocity and attenuation measurements, in addition to the transient pulse used in the Schlumberger method. Measurements were made on samples with accurately known compressional and shear wave properties and on replicated rock samples. The results demonstrate that the determinations of velocities are accurate to ± 0.3%, and that the determinations of attenuation are accurate to ±0.1 dB/cm at 0.85 MHz.
