Abstract:Ultrasonically-induced polarization is a nonlinear geophysical phenomenon that acoustic field in fluid-saturated porous medium changes into electromagnetic wave field while acoustic wave travels in the medium;in other words, it is also the process of acoustic energy changing into electromagnetic energy. Under low frequency condition,the wave field energies produced by acoustic source in both borehole and surrounding formation exist and travel along borehole wall mainly in the form of Stoneley wave,so that equation showing the process of ultrasonically-induced polarization may be reduced relatively. The authors modeled and analysed full wavetrain waveforms in low and high frequency cases in transversally-isotropic and homogeneous-isotropic fluid-saturated porous media. The theoretic model of low-frequency ultrasonically induced-polarization electric field is deduced systematically on the premise that there exists natural electric field in borehole. In addition, the concept and definition of sensitive coefficient of induced polarization is advanced also in the article.
周成当, 杨体源 . 井中低频声激发极化电场理论模型[J]. 石油地球物理勘探, 2000, 35(2): 193-201.
Zhou Chengdang, Yang Tiyuan. Theoretic model of low-frequency ultrasonically induced-polarization electric field in borehole. OGP, 2000, 35(2): 193-201.