PHASE-INDUCED POLARIZATION METHOD BASED ON PROCESSING NOISE SIGNALS OF THE NATURAL ELECTROMAGNETIC FIELD OF THE EARTH

2012 ◽  
Vol 10 (6) ◽  
pp. 453-468 ◽  
Author(s):  
Andreas Kemna ◽  
Andrew Binley ◽  
Giorgio Cassiani ◽  
Ernst Niederleithinger ◽  
André Revil ◽  
...  

Geophysics ◽  
1984 ◽  
Vol 49 (11) ◽  
pp. 2061-2063 ◽  
Author(s):  
James R. Wait

In a previous communication I proposed an analytical model to simulate the electromagnetic (EM) and induced polarization (IP) response of a metal well casing (Wait, 1983). To facilitate the analysis, the earth was idealized as a homogeneous conducting half‐space of electrical properties (σ, ε, μ). The well casing was represented as a filamental vertical conductor of semiinfinite length that was characterized by a series axial impedance to account for eddy currents and interfacial polarization. A further basic simplification was to neglect displacement currents in the air; this was justified when all significant distances were small compared with the free‐space wavelength. Initially, the source was taken to be a horizontal electric dipole or current element I ds on the air‐earth interface. By integration of the results, the mutual impedance between two grounded circuits could be ascertained. In the absence of the vertical conductor (i.e., the well casing) the results reduced to those given by Sunde (1968) and Ward (1967).


Geophysics ◽  
1994 ◽  
Vol 59 (9) ◽  
pp. 1327-1341 ◽  
Author(s):  
Douglas W. Oldenburg ◽  
Yaoguo Li

We develop three methods to invert induced polarization (IP) data. The foundation for our algorithms is an assumption that the ultimate effect of chargeability is to alter the effective conductivity when current is applied. This assumption, which was first put forth by Siegel and has been routinely adopted in the literature, permits the IP responses to be numerically modeled by carrying out two forward modelings using a DC resistivity algorithm. The intimate connection between DC and IP data means that inversion of IP data is a two‐step process. First, the DC potentials are inverted to recover a background conductivity. The distribution of chargeability can then be found by using any one of the three following techniques: (1) linearizing the IP data equation and solving a linear inverse problem, (2) manipulating the conductivities obtained after performing two DC resistivity inversions, and (3) solving a nonlinear inverse problem. Our procedure for performing the inversion is to divide the earth into rectangular prisms and to assume that the conductivity σ and chargeability η are constant in each cell. To emulate complicated earth structure we allow many cells, usually far more than there are data. The inverse problem, which has many solutions, is then solved as a problem in optimization theory. A model objective function is designed, and a “model” (either the distribution of σ or η)is sought that minimizes the objective function subject to adequately fitting the data. Generalized subspace methodologies are used to solve both inverse problems, and positivity constraints are included. The IP inversion procedures we design are generic and can be applied to 1-D, 2-D, or 3-D earth models and with any configuration of current and potential electrodes. We illustrate our methods by inverting synthetic DC/IP data taken over a 2-D earth structure and by inverting dipole‐dipole data taken in Quebec.


2019 ◽  
Vol 27 (3) ◽  
pp. 466-477 ◽  
Author(s):  
E. D. Kuzmenko ◽  
S. M. Bahrii ◽  
U. O. Dzioba

On the basis of the analysis of the literature sources, we determined the possible range of using the method of the Earth`s natural pulse electromagnetic field. As a result of detailed analysis of domestic and foreign research, we demonstrated the relevance of conducting research focused on development of the Earth'snatural pulse electromagneticfield (or ENPEMF). Using the results of theoretical studies, the advantages and disadvantages of the ENPEMF method were determined. A complex of physical processes which preceded the development of the pulse electromagnetic field of the Earth was characterized, and the impact of mechanical deformations of rocks on the change in the condition of the electromagnetic field was experimentally proven. The main fundamentals on the determination of depth range of the ENPEMF method were examined and a new approach to interpretation of the data was suggested. We conducted an analysis of methods developed earlier of calculating geometric parameters of the sources which generate electromagnetic impulses. Their practicability at a certain stage of solving the data of geological tasks was experimentally tested. We determined the factors which affect the depth range of the ENPEMF method. A mathematical solution of the effectiveness of the ENPEMF method was suggested and determined the relations between the depth parameter of the study and the frequency of measuring and effective value of specific electric resistance. On the example of different objects, the effectiveness and correctness of the suggested method of determining the depth range parameter was proven. In particular, the theoretical results of the study were tested and confirmed on objects of different geological-morphological and engineering-technical aspects, i.e. Novo-Holyn mine in the Kalush-Holynske potash deposit and the multi-storey educational building of the University in Ivano-Frankivsk. The practicability of using the ENPEMF method in combination with other methods of electrometry for solving practical geological tasks was experimentally proven.


2021 ◽  
Vol 2078 (1) ◽  
pp. 012035
Author(s):  
Qingxin Meng ◽  
Zhigang Wang ◽  
Yao Lu ◽  
Guoyuan Hang

Abstract Surface-hole induced polarization method is a typical deep resource exploration technology, which plays an important role in the mineral survey. The traditional surface-hole induced polarization method is mainly to observe a single polarized secondary field. At present, the time spectrum observation of polarization fields is becoming more and more popular, which greatly enriches the interpretation technology of induced polarization data. In this work, the time spectrum induced polarization method is expounded, the decay polarization fields were numerical calculated and analyzed for the typical 2-dimensional geoelectric model. The results show that for a single polarized target, the time spectrum obtained from different azimuth observation responses are basically the same, which can effectively reflect the time-varying characteristics of the polarized fields. The observation responses of polarized target at different depths can still reflect the time spectrum of decay fields. The main change of the observed response of the polarized target closer to the borehole is the response amplitude. The conclusions and simulations of this study can provide working mode for relevant research and reference for similar work.


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