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| | Abstract | | Seismic attenuation is a highly variable physical parameter that depends on confining pressure, porosity, degree of fluid saturation, and variations in fluid properties such as elastic modulus, viscosity, and polarity. In our previous paper, we used partially frozen brine as a solid-liquid coexistence system to investigate seismic attenuation phenomena. This paper is concerned with the effect of such viscosity on attenuation at ultrasonic frequencies. We observed the variations of a transmitted wave, changing its salinity and quantitatively estimated attenuation for unconsolidated porous material saturated with brine by considering different distances between the source and receiver transducers. The waveform analyses for P-waves indicate that the attenuation increases with increasing salinity (i.e. increasing viscosity). In order to elucidate the physical mechanism responsible for ultrasonic wave attenuation measured at different salinity (i.e. different viscosity), we employ a poroelastic model based on the Biot theory to describe the propagation of ultrasonic waves through partially frozen brines. |
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