Electromagnetic Waves Attenuation in the Sandstones With Grains of Different Size at Imbibition and Drying

Abstract

Abstract-The results of experimental measurements of the complex dielectric permittivity (CDP) of powders of quartz granules with different sizes saturated with water and salt solution of weak concentration are given in the frequency band from 20 kHz to 1 GHz. It is shown that at values of saturation level from 0.6 to 0.9 the relaxation phenomena caused by interfacial polarization on the water-air bound can be observed. The result shows considerable reduction of attenuation in gradually saturated rocks, which allows for deeper sensing during georadar mapping. It is determined that in the dielectric relaxation band and at frequencies below it the hysteresis of the real part of the CDP and equivalent specific conductivity can be observed. Its character significantly depends on the sizes of granules. It is shown that the behavior of CDP and attenuation of an electromagnetic wave at frequencies from 0.1 to 10 MHz complicatedly depends on the sizes of granules, saturation level, salinity of the saturating solution and saturation history.

Hysteresis of the NMR response and the complex relative permittivity of the quartz granules powders and solid sandstones during the water imbibition and drainage

“…The existence of the phenomenon of a hysteresis testifies that CRP of rocks at frequencies of 10 kHz-1 MHz depends directly on saturation history. It is shown in [10,11] that the phenomenon of hysteresis in specific conductivity and the real part of the CRP at moistening/drainage is tightly associated with the phenomenon of the dielectric relaxation that occurs in the rock at the presence of the water-air interface.…”