LAUSR

Based on the assumptions of Hudson theory, we built nine physical models, eight of which contain penny-shaped inclusions used to simulate fractures. The fracture density of the eight fractured model ranges from 2% to 12%. In the case that the fracture size was smaller than the wavelength, P- and S-wave transducers with three different ultrasound frequencies were used to estimate the P- and S-wave velocities of the matrix and inclusions from the travel time picks and distance measurements. The experimentally obtained velocities were substituted into the Hudson’s model to calculate the theoretical velocities and anisotropy of fractured models, which were then compared with the experimental values of velocities and anisotropy. Generally, with the variation of fracture density, the experimental results agreed well with the theoretical estimations within the frequency range from 0.10 MHz to 0.50 MHz. The experimental values of P- and S-wave velocities and anisotropy showed conspicuous dispersion. With the decr...