Acoustic velocities and attenuation in sandstones as a function of effective stress: measurements and modelling

Compressional and shear-wave velocities have been measured and a novel approach using digital processing employed to study wave attenuation for brine- and gas-saturated sandstones, over a range of effective stresses from 5 to 60 MPa. The complex resistivity has also been measured in the brine-saturated state and permeability in the gas-saturated state over the same range of the stresses as that for the velocity measurements. Broadband ultrasonic pulses of P- and orthogonally polarised S-waves in the frequency range 0 .3-0 .6 MHz are transmitted through the specimen to be characterised for comparison with a reference (aluminium) having low attenuation .