RECENT ADVANCES AND APPLICATIONS IN COMPLEX RESISTIVITY MEASUREMENTS

Geophysics ◽  
1975 ◽  
Vol 40 (5) ◽  
pp. 851-864 ◽  
Author(s):  
Kenneth L. Zonge ◽  
Jeffrey C. Wynn
Keyword(s):  
Host Rock ◽  
Electromagnetic Coupling ◽  
Field Measurements ◽  
Complete Removal ◽  
Induced Polarization ◽  
Laboratory Measurements ◽  
Spectral Measurements ◽  
Complex Resistivity ◽  
Geophysical Interpretation ◽  
Rock Alteration

Several years of accumulating complex resistivity spectral measurements have indicated that there are still many unexplored areas in induced polarization surveying that need to be investigated for a more complete understanding of the polarization process. In addition to providing mineral discrimination capabilities, complex resistivity spectra can be used to differentiate between various barren host rock responses, to facilitate the complete removal of electromagnetic coupling, and to identify pipeline, fence, and various other cultural coupling effects. Results of field measurements are presented in an effort to demonstrate the utility of and necessity for making complete spectral measurements for serious geophysical interpretation. Correlation of field measurements with laboratory measurements on core samples from the same area demonstrates that strong electromagnetic coupling can be accurately removed from complete spectra without removing the important rock response. Recent field and laboratory measurements indicate that most, if not all, induced polarization responses attributed to magnetite are not really due to this mineral but can be traced to a host rock alteration response. Also, characteristic host rock signatures for sulfide environments appear to vary according to locality and type of deposits making it impossible to provide a universal set of signatures for sulfide deposits.

EM COUPLING, ITS INTRINSIC VALUE, ITS REMOVAL AND THE CULTURAL COUPLING PROBLEM

Geophysics ◽  
1975 ◽  
Vol 40 (5) ◽  
pp. 831-850 ◽  
Author(s):  
Jeffrey C. Wynn ◽  
Kenneth L. Zonge
Keyword(s):  
Electromagnetic Induction ◽  
Electromagnetic Coupling ◽  
Intrinsic Value ◽  
Low Frequency ◽  
Induced Polarization ◽  
Electrode Polarization ◽  
Electrically Conductive ◽  
Coupling Problem ◽  
Complex Resistivity ◽  
Deep Sounding

The induced polarization method of geophysical prospecting has been in use for more than 25 years with varying degrees of success. Until recently, its two principle drawbacks were (1) the inability to distinguish between anomalous rock responses and, (2) inability to distinguish between these rock responses and inductive coupling. The first problem was solved by K. L. Zonge in 1972. Solutions to the coupling problem go back to 1932, and have been expanded and elaborated upon by successive authors since then. In most of these papers, electromagnetic coupling was separated into two functions, here designated as P, a purely inductive term, and Q, a grounding or purely resistive term. This paper extends this work into a study of the reflective coupling contribution and the effects of anisotropy. Two immediate results are: (a) the development of an ultra‐low‐frequency deep sounding technique for highly conductive overburden environments, and (b) a successful iterative technique for the removal of coupling from complex resistivity field data. A study was made of the effect of electrically conductive pipelines on induced polarization and complex resistivity data. It appears that the so‐called “pipeline effect” is a composite of several effects, including current focusing nonlinearities, electromagnetic induction, and complex electrode polarization. The pipeline effect is generally predictable, while the effect of a fence or an irregular conductive inhomogeneity is not as simple.

A STUDY IN INDUCED POLARIZATION

Geophysics ◽  
1964 ◽  
Vol 29 (5) ◽  
pp. 848-864 ◽  
Author(s):  
L. A. Anderson ◽  
G. V. Keller
Keyword(s):  
High Field ◽  
Field Measurements ◽  
Induced Polarization ◽  
Laboratory Measurements ◽  
Polarization Measurements ◽  
The Matrix ◽  
Current Densities ◽  
Matrix Resistivity ◽  
Background Effect

Induced polarization in pyritic sandstone arises in part from overvoltage effects and in part from electrolytic polarization. Because induced‐polarization measurements are commonly used to search for sulfides, the electrolytic polarization is an undesirable background effect. Pyrite in sandstone can be located only when overvoltage polarization substantially exceeds electrolytic polarization. Laboratory measurements indicate this is true only if there is ten percent or more pyrite in a rock. However, overvoltage polarization is much larger when low current densities are used, particularly if the matrix resistivity is high. Field measurements indicate that at low current densities as little as one or two percent pyrite may provide sufficient overvoltage polarization to be recognizable in the presence of electrolytic polarization.

Saturated Hydraulic Conductivity of Clayey Tills and the Role of Fractures

1990 ◽  
Vol 21 (2) ◽  
pp. 119-132 ◽  
Author(s):  
Johnny Fredericia
Keyword(s):  
Hydraulic Conductivity ◽  
American Studies ◽  
Field Measurements ◽  
Present Knowledge ◽  
Saturated Hydraulic Conductivity ◽  
Field Observations ◽  
Laboratory Measurements ◽  
Vertical Hydraulic Conductivity ◽  
Data Field

The background for the present knowledge about hydraulic conductivity of clayey till in Denmark is summarized. The data show a difference of 1-2 orders of magnitude in the vertical hydraulic conductivity between values from laboratory measurements and field measurements. This difference is discussed and based on new data, field observations and comparison with North American studies, it is concluded to be primarily due to fractures in the till.

Aerosol Properties and Processes: A Path from Field and Laboratory Measurements to Global Climate Models

2007 ◽  
Vol 88 (7) ◽  
pp. 1059-1084 ◽  
Author(s):  
Steven J. Ghan ◽  
Stephen E. Schwartz
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Field Measurements ◽  
Substantial Improvement ◽  
Global Climate Models ◽  
Department Of Energy ◽  
Lower Atmosphere ◽  
Laboratory Measurements ◽  
Successive Generations ◽  
Aerosol Properties

Aerosol particles in the lower atmosphere exert a substantial influence on climate and climate change through a variety of complex mechanisms. Consequently, there is a need to represent these influences in global climate models, and models have begun to include representations of these influences. However, the present treatment of aerosols in global climate models is highly simplified, omitting many processes and feedbacks that are thought to be climatically important. Thus, there is need for substantial improvement. Here we describe the strategy of the U.S. Department of Energy for improving representation of the properties, processes, and effects of tropospheric aerosols in global climate models. The strategy begins with a foundation of field and laboratory measurements that provide the basis for modules describing specific aerosol properties and processes. These modules are then integrated into regional aerosol models, which are evaluated by comparison with field measurements. Issues of scale are then addressed so that the modules can be applied to global aerosol models, which are evaluated by comparison with satellite retrievals and other observations. Finally, the validated set of modules is applied in global climate models for multicentury simulations. This strategy is expected to be applied to successive generations of global climate models.

A special circumstance of airborne induced‐polarization measurements

Geophysics ◽  
1996 ◽  
Vol 61 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Richard S. Smith ◽  
Jan Klein
Keyword(s):  
Time Domain ◽  
Eddy Currents ◽  
High Arctic ◽  
Induced Polarization ◽  
Laboratory Measurements ◽  
Dielectric Polarization ◽  
Special Circumstance ◽  
Polarization Measurements ◽  
Airborne Electromagnetic

Airborne induced‐polarization (IP) measurements can be obtained with standard time‐domain airborne electromagnetic (EM) equipment, but only in the limited circumstances when the ground is sufficiently resistive that the normal EM response is small and when the polarizability of the ground is sufficiently large that the IP response can dominate the EM response. Further, the dispersion in conductivity must be within the bandwidth of the EM system. One example of what is hypothesized to be IP effects are the negative transients observed on a GEOTEM® survey in the high arctic of Canada. The dispersion in conductivity required to explain the data is very large, but is not inconsistent with some laboratory measurements. Whether the dispersion is caused by an electrolytic or dielectric polarization is not clear from the limited ground follow‐up, but in either case the polarization can be considered to be induced by eddy currents associated with the EM response of the ground. If IP effects are the cause of the negative transients in the GEOTEM data, then the data can be used to estimate the polarizabilities in the area.

On: “Recent Advances and Applications in Complex Resistivity Measurements,” by K. L. Zonge and J. C. Wynn (GEOPHYSICS, Oct. 1975, p. 851–864)

Geophysics ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 120-121 ◽  
Author(s):  
P. H. Nelson ◽  
G. D. Van Voorhis
Keyword(s):  
Spectral Data ◽  
Induced Polarization ◽  
Complex Resistivity ◽  
Resistivity Measurements ◽  
Recent Advances ◽  
Measuring Techniques

In presenting a variety of induced polarization spectral data, Zonge and Wynn refer to a paper published earlier by us (Van Voorhis et al., 1973) which deals with the same topic. We feel Zonge and Wynn have misrepresented our measuring techniques, data, and conclusions in their references to our paper. Our principal objections center on three statements by the authors.

scholarly journals USB-based radiation monitor

2006 ◽  
Vol 21 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Vujo Drndarevic ◽  
Nenad Jevtic ◽  
Radivoje Djuric
Keyword(s):  
Gamma Probe ◽  
Field Measurements ◽  
Laboratory Measurements ◽  
Laptop Computer ◽  
Universal Serial Bus ◽  
Peripheral Device ◽  
Radiation Monitor ◽  
Labview Software ◽  
Flexible Instrument ◽  
Usb Bus

The Universal Serial Bus has become a dominant interface for the connection of standard peripheral devices to a PC computer. This paper analyzes the possibilities of USB bus applications in the field of measurement and environmental monitoring. As a result, a gamma radiation monitor consisting of an USB-based universal peripheral device and a gamma probe with a GM counter, has been designed. For the interfacing monitor with the powerful and easy to use LabVIEW software package, an instrument driver as a set of virtual instruments has been developed. The proposed monitor is a flexible instrument which can be used for laboratory measurements, as an environ mental radiation monitor or for training purposes. Connected to the laptop computer, the monitor becomes a portable instrument suitable for field measurements. Basic measurements and functionality properties of the radiation monitor are presented here.

A hybrid correlation denoising method based on complex resistivity and application on spread spectrum induced polarization data

Geophysics ◽  
2021 ◽  
pp. 1-35
Author(s):  
Siming He ◽  
Jian Guan ◽  
Yi Wang ◽  
Xiu Ji ◽  
Hui Wang
Keyword(s):  
Hybrid Method ◽  
Spread Spectrum ◽  
Field Experiments ◽  
Noise Suppression ◽  
Random Noise ◽  
Induced Polarization ◽  
Data Simulation ◽  
Denoising Method ◽  
Complex Resistivity ◽  
Geophysical Surveys

In electrical exploration techniques, an effective suppression method for Gaussian and impulsive random noise in spread spectrum induced polarization (SSIP) continues to be challenging for conventional denoising methods. Remnant noise influences the complex resistivity spectrum and damages the subsequent interpretation of geophysical surveys. We present a hybrid method based on a correlation function and complex resistivity, which introduces the correlation analyses between the transmitting source, the measured potential, and the injected current signal. According to the analyses, reliable results for complex resistivity spectra can be calculated, which can be further used for noise suppression. We apply the hybrid method to both numerical and field experiments to process measured SSIP data. Simulation tests show that the hybrid method not only suppresses the two types of noise but also improves the relative error of the complex resistivity spectrum. Field data processing shows that the hybrid method can minimize the standard deviation of the data and possess a greater ability to distinguish adjacent objects, which can improve the reliability of the data in subsequent processing and interpretation.

The measurement and analysis of complex resistivity and induced polarization of shale cores

2016 ◽  
Author(s):  
Juan Chen ◽  
Tao Huang ◽  
Gang Yu ◽  
Zhanxiang He ◽  
Xuben Wang ◽  
...  
Keyword(s):  
Induced Polarization ◽  
Complex Resistivity ◽  
Measurement And Analysis
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