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Simulation of Monopole and Multipole Seismoelectric Logging

DOI: 10.1155/2011/107827

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Abstract:

In a fluid-saturated porous formation, acoustics and electromagnetic waves are coupled based on Pride seismoelectric theory. An exact treatment of the nonaxisymmetric seismoelectric field excited by acoustic multipole sources is presented. The frequency wavenumber domain representations of the acoustic field and associated seismoelectric field due to acoustic multipole sources are formulated. The full waveforms of acoustic waves and electric and magnetic fields in the time domain propagation in borehole are simulated by using discrete wave number integration, and frequency versus axial-wave number responses are presented and analyzed. 1. Introduction The study of wave propagation in a fluid-saturated porous medium is of considerable interest in acoustics and geophysics due to its important applications in various technical and engineering processes. The investigation of wave propagation in fluid-saturated porous media was early developed by Biot [1, 2]. One of the major findings of Biot’s theory was that there is a compressional slow wave in a fluid-saturated porous medium. The first clear experimental observation of this slow wave was reported by Plona [3]. Biot predicted the slow waves should have an important bearing on electrokinetic effect [4]. This predication has been quantitatively confirmed by Pride [5] and Hu [6]. Elastic waves propagating in fluid-saturated porous media generate a movement of the ions in the pore fluid. Such movement induces an electromagnetic (EM) field. Thompson and Gist [7] have made field measurement clearly demonstrating that seismic waves can induce electromagnetic disturbances in saturated sediments. Pride [8] derived the governing equations for the coupled acoustics and electromagnetic waves in fluid-saturated porous media. Pride and Haartsen [9] analyzed the basic properties of seismoelectric waves. The electric field induced by elastic waves is weak and attenuates in propagation. In order to detect the seismoelectric signal effectively, Haartsen and Pride [10] suggested measuring vertical electroseismic profile. Mikhailov et al. [11] measured the electric field converted from low frequency Stoneley waves in a borehole and made theoretical analysis. Seismoelectric logging method has been proposed to detect deep target formation. The advantage of seismoelectric logging is the distance both from transmitter to target formation and from the transmitter to the receiver is small, and signals can be received with relative high amplitude. Zhu et al. [12–14] made laboratory experiments and observed the seismoelectric

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