Home – Home – Jornals – Russian Geology and Geophysics 2011 number 5

This paper presents the results of experiments on the effect of variable amplitude and pressure on the P -wave velocity and attenuation in cemented sandstone sample. The measurements were performed in transmitted waves at a predominant pulse frequency of 6.8 kHz in the range of strain amplitudes A ^ε ≈ (0.2-2.4) ·10^-6 at an axial static pressure of 0.25 MPa to 1.0 MPa. The wave velocity depends weakly on the amplitude and decreases only slightly with its increase. With increasing pressure the velocity v_e nonlinearly increases (to 6 %) at all amplitudes. The attenuation Q_e increases linearly (to 2.5 %) with increasing amplitude and decreases nonlinearly with increasing pressure. There is an anomalous change in the attenuation in the pressure range (0.5-0.75) MPa, where it decreases to 30 % at all amplitudes. These results may be useful for improving acoustic and seismic methods of diagnostics.