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Technical Papers

Index

Processing gradients of magnetic data utilizing an equivalent source technique
2007. Ruizhong Jia and R.W. Groom
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Enhancing Model Reliability from TEM Data Utilizing Various Multiple Data Strategies
2007. Ruizhong Jia, R.W. Groom. SAGEEP.
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Enhancing Model Reliability from TEM Data Utilizing Various Multiple Data Strategies
2007. Ruizhong Jia, R.W. Groom. KEGS.
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Aerial Transient Electromagnetic Surveys of Alluvial Aquifers in Rural Watersheds of Arizona, United States
2006. Poole, Callegary and Groom. AGU.
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Processing gradients of magnetic data utilizing an equivalent technique. Internal paper.
2006. Ruizhong Jia, R.W. Groom. SEG.
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Vertical Spatial Sensitivity and Exploration Depth of Low-Induction-Number Electromagnetic-Induction Instruments
2006. James B. Callegary, Ty P.A. Ferré and R.W. Groom
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Magnetic Case Study: Raglan Mine
2006. Laura Davis.
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Geophysical case study of the Iso and New Insco deposits, Québec, Canada: Part II, modeling and interpretation
2006. Li Zhen Cheng. Reviewed Draft.
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Comparison of Theoretical and Physical Model Studies of the Responses of Moving Source and Fixed Loop Electromagnetic Exploration Systems
2005. K. Duckworth. Pure and Applied Geophysics.
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On some issues regarding 3D-gravity inversion
2005. Ruizhong Jia, R.W. Groom. SEG. 75 Annual Meeting, Houston, TX.
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On Time-Domain Transient Electromagnetic Soundings, Extended Abstract
2005. Ruizhong Jia and Ross Groom. SAGEEP.
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Final Report On Improved Aeromagnetic Compensation: A New Aircraft Compensation System for Magnetic Terrains
2004. John Jia, Bob Lo, Ross Groom. Unpublished Report.
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The Use of GPS Sensors and Numerical Improvements in Aeromagnetic Compensation. Extended Abstract
2004. Ruizhong Jia, R.W. Groom, Bob Lo. SEG. 74th SEG Conference, Denver, USA.
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Magnetic Compensation of magnetic noise related to aircraft's maneuvers in airborne survey. Extended Abstract
2004. R.W. Groom, Ruizhong Jia, Bob Lo. SAGEEP.
read summary or download paper (PDF) or presentation (PDF)
On Inversion of Gradient Magnetic Data for Detection of Multiple Buried Metallic Objects. Extended Abstract
2004. Ruizhong Jia, R.W. Groom. SAGEEP.
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Investigations into Inversion of Magnetic and Gradient Magnetic Data for Detection and Discrimination of Metallic Objects. Extended Abstract
2003. R.W. Groom, Ruizhong Jia, C. Alvarez. SAGEEP.
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3D EM Modelling - Application of the Localized Non-Linear Approximator to Near Surface Applications. Extended Abstract
2002. R. Groom, C. Alvarez. SAGEEP.
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Some Pitfalls in Gradient Magnetic Processing or Why Rotate Gradients
2002. R.W. Groom, Bob Lo. KEGS.
read summary or download presentation (PDF)
Improved Depth Distributions by Inversion of Magnetic Surveys Collected at Different Survey Heights
2002. Bob Lo, R.W. Groom. KEGS.
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Development in a normal mode helical electrical antennae crosshole instrumentation and integrated interpretation system. Extended Abstract
2001. R.W. Groom, C. Candy. SAGEEP.
read summary or download paper (PDF) or presentation (PDF)
X-hole Tomography. A New Frontier in Equipment and Software
2001. R.W. Groom, C. Candy. KEGS.
read summary or download presentation (PDF)
An Interpretation Study of Pulse EM Reconnaissance Data from the Raglan Belt of Northern Canada, Extended Abstracts
1999. Groom, R.W., Murray, Alvarez, C., North, J. 3D Symposium, Utah, Colorado.
read summary or download paper (PDF)
Modelling of complex electromagnetic targets using advanced non-linear approximator techniques, Extended Abstracts
1999. Murray, I. R., Alvarez, C. and Groom, R.W. 69th SEG Conference, Houston, Texas.
read summary or download paper (PDF)
On Extending the Localized Non-Linear Approximation to Inductive Modes Extended Abstracts
1997. Murray, I.R. F004, 59th EAGE Conference, Geneva, Switzerland.
read summary or download paper (PDF)
A case study on the application of the EMIGMA modelling package to Crone data over the SOQUEM Lac Volant Region, Sept-Îles, Québec, Extended Abstracts
1996. Parker, D.H, Boivin, M., Murray, I. R and Groom, R.W. 67th SEG Conference, Dallas, Texas.
read summary or download paper (PDF)
A case study of the application of the EMIGMA modelling package in interpretation of UTEM data over the Cominco Cerattepe deposit in Turkey, Extended Abstracts
1996. Groom, R.W., Hyde, C.H. and Lajoie, J. 66th SEG Conference, Denver, Colorado.
read summary or download paper (PDF)
Beyond the Born and Rytov Approximations: A Nonlinear Approach to Electromagnetic Scattering
1993. Habashy T. M, Groom, R.W. and Spies. B.R. J. Geophys Res., 98, no. B2, p. 1759-1775.
read summary or download paper (PDF)

Full Listing

Title:: Processing gradients of magnetic data utilizing an equivalent source technique
By:: 2007. Ruizhong Jia and R.W. Groom
Download:: presentation (PDF)

Title:: Enhancing Model Reliability from TEM Data Utilizing Various Multiple Data Strategies
By:: 2007. Ruizhong Jia, R.W. Groom. SAGEEP.
Download:: presentation (PDF)

Title:: Enhancing Model Reliability from TEM Data Utilizing Various Multiple Data Strategies
By:: 2007. Ruizhong Jia, R.W. Groom. KEGS.
Download:: presentation (PDF)

Title:: Aerial Transient Electromagnetic Surveys of Alluvial Aquifers in Rural Watersheds of Arizona, United States
By:: 2006. Poole, Callegary and Groom. AGU.
Download:: poster (PDF)

Title:: Processing gradients of magnetic data utilizing an equivalent technique. Internal paper.
By:: 2006. Ruizhong Jia, R.W. Groom. SEG.
Download:: paper (PDF)

Title:: Vertical Spatial Sensitivity and Exploration Depth of Low-Induction-Number Electromagnetic-Induction Instruments
By:: 2006. James B. Callegary, Ty P.A. Ferré and R.W. Groom
Description:: Vertical spatial sensitivity and effective depth of exploration (d_e) of low-induction-number (LIN) frequency-domain electromagnetic-induction instruments over a layered soil were evaluated using a complete numerical solution to Maxwell's equations. Previous studies using approximate mathematical solutions predicted a vertical spatial sensitivity for instruments operating under LIN conditions that, for a given transmitter-receiver coil-separation (s), coil orientation and transmitter frequency (ω), should depend solely on depth below the land surface. When not operating under LIN conditions, vertical spatial sensitivity and de also depend on apparent soil electrical conductivity (σ_a) and therefore the induction number (β) which is directly proportional to σ_a. In this new evaluation, we determine the range of σ_a and β values for which the LIN conditions hold and how d_e changes when they do not.
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Title:: Magnetic Case Study: Raglan Mine
By:: 2006. Laura Davis.
Description:: The objective of this study was to test the tools available in EMIGMA (PetRos Eikon) for their utility in analyzing magnetic data in terms of the usefulness and efficiency of available algorithms and the ease of using the interface. Many different types of tools were used together to get a clear understanding of the geophysics of the problem, and what the geophysics means for the structure of the subsurface. For the purpose of this testing, field data from a portion of the Raglan Mine site was examined.
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Title:: Geophysical case study of the Iso and New Insco deposits, Québec, Canada: Part II, modeling and interpretation
By:: 2006. Li Zhen Cheng. Reviewed Draft.
Description:: The MEGATEMII data collected over the Iso and New Insco bodies have been modelled using three modeling packages. The EMQ package is a quick inversion tool which indicates that the Iso body is a dipping plate-like body. The New Insco body is inferred to have a geometry somewhere between a dipping plate and a sphere. The Maxwell package was used to refine the properties of the plate-like body at Iso. The EMIGMA package was able to identify which parts of the New Insco orebody were more conductive. It was observed that the most conductive parts correspond to the copper-rich zones and the next most conductive to the pyrite-rich zone. The EMIGMA package was also used to show that a thick-prism model might be a more appropriate model for the New Insco ore body.
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Title:: Comparison of Theoretical and Physical Model Studies of the Responses of Moving Source and Fixed Loop Electromagnetic Exploration Systems
By:: 2005. K. Duckworth. Pure and Applied Geophysics.
Description:: Theoretical and physical scale model responses for moving source and fixed loop electromagnetic exploration systems are presented for the case of a vertical, thin, plate conductor located first in free-space and then in a conductive host. The results are presented in the form of anomaly index diagrams plotted in complex space. The two modeling approaches show general agreement on the behavior of the current gathering effect that operates when the conductive host is present. Both approaches show an onset of a strong positive effect at higher frequencies in the responses provided by both horizontal coplanar coil systems and by fixed loop systems. Agreement is also shown on an unanticipated negative effect that a conductive host causes in the responses provided by the vertical coplanar coincident coil system. Both modeling approaches demonstrate that the responses provided by fixed loop systems are predominantly caused by the current gathering effect. The extent of this effect for fixed loop systems depends on the size of the transmitter loop with respect to the target and on the depth of the target. The theoretical modeling demonstrates that both moving source and fixed loop systems operated over a target located in a conductive host, provide responses that become almost identical and independent of the conductance of the target at high frequency.
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Title:: On some issues regarding 3D-gravity inversion
By:: 2005. Ruizhong Jia, R.W. Groom. SEG. 75 Annual Meeting, Houston, TX.
Description:: We used our forward simulation algorithms to generate the vertical component of gravity field (Gz) on the ground surface and the airborne data Gzz which is the spatial vertical derivative of Gz. We applied our inversion technique to synthetic ground data and airborne data. The results of this work demonstrates that in some cases the Euler deconvolution technique plays important role in enhancing our 3D-gravity inversion.
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Title:: On Time-Domain Transient Electromagnetic Soundings, Extended Abstract
By:: 2005. Ruizhong Jia and Ross Groom. SAGEEP.
Description:: Some issues in modelliing TEM responses and their relevance to real-world systems and geology.
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Title:: Final Report On Improved Aeromagnetic Compensation: A New Aircraft Compensation System for Magnetic Terrains
By:: 2004. John Jia, Bob Lo, Ross Groom. Unpublished Report.
Description:: Leliak's system of equations, first published over 30 years ago for served magnetometers, remains today the standard for aeromagnetic compensation using multiple strapdown sensors. This project examines the fundamentals of Leliak's system of equations to gain understanding into aeromagnetic compensation.
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Title:: The Use of GPS Sensors and Numerical Improvements in Aeromagnetic Compensation. Extended Abstract
By:: 2004. Ruizhong Jia, R.W. Groom, Bob Lo. SEG. 74th SEG Conference, Denver, USA.
Description:: The results of this work demonstrate that it is possible to use three well-spaced GPS receivers on an aircraft to measure the aircraft attitude to the precision required to compensate for the aircraft effects. The experiments with the different highpass filters used on the data and with the different solvers indicate that with the proper selection of filters and solvers, better compensation results can be obtained.
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Title:: Magnetic Compensation of magnetic noise related to aircraft's maneuvers in airborne survey. Extended Abstract
By:: 2004. R.W. Groom, Ruizhong Jia, Bob Lo. SAGEEP.
Description:: An aircraft or helicopter emanates magnetic signals. These signals owe to a number of factors including induced fields due to magnetically susceptible and permanent magnetic materials on the platforms as well as both induced electromagnetic signals and electromagnetic signals generated either by electrical systems or moving parts such as rotors. This paper discusses the problems and techniques related to removing the effects of the moving platform and makes an attempt to study the subject with the use of simulated data.
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presentation (PDF)

Title:: On Inversion of Gradient Magnetic Data for Detection of Multiple Buried Metallic Objects. Extended Abstract
By:: 2004. Ruizhong Jia, R.W. Groom. SAGEEP.
Description:: In previous works, the authors developed algorithms to implement an Euler depth estimator as well as an inversion algorithm for detecting a simple dipole, which is often a suitable model for UXO applications. These algorithms worked independently with a single anomaly. In the present paper, a combination of these algorithms is used to determine the locations and the internal magnetization vectors of multiple buried objects in a practical field survey.
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Title:: Investigations into Inversion of Magnetic and Gradient Magnetic Data for Detection and Discrimination of Metallic Objects. Extended Abstract
By:: 2003. R.W. Groom, Ruizhong Jia, C. Alvarez. SAGEEP.
Description:: Three-dimensional magnetic modeling capabilities have been extended to simulate TMI, magnetic vector and gradient measurements for both permanent magnetization and strong induced effects. It is possible now to model quite general 3D shapes including conical and cylindrical objects both solid and hollow. These general shapes can be combined to represent projectile shells with quite general shapes having varying internal magnetic properties. Based on these simulation capabilities, the use of inversion algorithms is investigated for determining the internal magnetization vector of buried objects.
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Title:: 3D EM Modelling - Application of the Localized Non-Linear Approximator to Near Surface Applications. Extended Abstract
By:: 2002. R. Groom, C. Alvarez. SAGEEP.
Description:: Rapid O(N) numerical techniques were initially developed for hydrocarbon reservoir characterization and later for mineral exploration. Now they are proving useful for near-surface environmental and geotechnical applications. The general formulation of the techniques provides extensions to simulation problems of specific interest for near-surface EM, such as the simulation of induction effects due to contrasts solely in induced magnetization and the combined response due to contrasts in resistivity and magnetization. The use of the original techniques as well as research into new extensions as they pertain to near-surface applications is discussed
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Title:: Some Pitfalls in Gradient Magnetic Processing or Why Rotate Gradients
By:: 2002. R.W. Groom, Bob Lo. KEGS.
Description:: A number of gradient derivation examples are considered: (1) derivation of TMI gradients in three-sensor magnetic processing; (2) generation of analytic gradients for benchmarking from fully synthetic data; (3) gradient derivation from simulated data with true flight and orientation information, and (4) gradient derivation from real data.
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Title:: Improved Depth Distributions by Inversion of Magnetic Surveys Collected at Different Survey Heights
By:: 2002. Bob Lo, R.W. Groom. KEGS.
Description:: The presentation describes the ability of EMIGMA to use in inversions data from different elevations. This feature seems to improve the distribution of magnetic material in the models providing a more accurate estimation of the depth to top and bottom.
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Title:: Development in a normal mode helical electrical antennae crosshole instrumentation and integrated interpretation system. Extended Abstract
By:: 2001. R.W. Groom, C. Candy. SAGEEP.
Description:: New instrumentation including a single-antenna NMHA system and a compact downhole device is offered for effective multi-frequency investigation of different environments. Simulation capabilities developed both for the antennae radiation pattern and electromagnetic wave scattering in a three-dimensional environment provide for contrasts in resistivity, electrical permittivity and magnetic permeability. Suggested tomographic techniques allow for near-field scattering and curved boreholes. Data are presented from a calibration site with detailed logs, a landfill site with leachate contamination, an industrial site with industrial cleaning solution contamination, and a survey to study groundwater geometry in a glacial till environment.
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presentation (PDF)

Title:: X-hole Tomography. A New Frontier in Equipment and Software
By:: 2001. R.W. Groom, C. Candy. KEGS.
Description:: The X-hole tomography instrumentation and data interpretation methods are described. Survey test results are presented for glacio-fluvial environment, a municipal landfill test site, earthen dam and mine settings.
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Title:: An Interpretation Study of Pulse EM Reconnaissance Data from the Raglan Belt of Northern Canada, Extended Abstracts
By:: 1999. Groom, R.W., Murray, Alvarez, C., North, J. 3D Symposium, Utah, Colorado.
Description:: Several stages of interpretation of pulse EM data over a relatively complex geological setting are presented. Simulation of the electromagnetic data was critical to understanding the electromagnetic data. This simulation required the accurate reproduction of several physical mechanisms not to our knowledge previously available. These studies led to a better understanding of some basic physical responses potentially present in many data scenarios.
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Title:: Modelling of complex electromagnetic targets using advanced non-linear approximator techniques, Extended Abstracts
By:: 1999. Murray, I. R., Alvarez, C. and Groom, R.W. 69th SEG Conference, Houston, Texas.
Description:: The development of rapid O(N) numerical techniques, initiated by the pioneering of the Localized Non-Linear (LN) Approximator in 1993, offers many possibilities for the simulation of realistic electromagnetic situations for a wide range of applications. Very rapid calculation times combined with minimal memory requirements offer the potential to simulate more complex and thus more geologically meaningful models. This paper summarizes experiments with many developments in LN techniques, including extensions to inductive modes, multi-body problems, time-varying magnetic effects and polyhedral primitives.
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Title:: On Extending the Localized Non-Linear Approximation to Inductive Modes Extended Abstracts
By:: 1997. Murray, I.R. F004, 59th EAGE Conference, Geneva, Switzerland.
Description:: A large loop inductive excitation is modeled to illustrate the use of approximate methods for simulating complex physical models in small geophysical environments where computing resources are limited. Comparisons with other existing scattering algorithms have shown the technique to be very effective at modeling inductive response, with computation times being significantly faster than those of the algorithms lately designed specifically for speed. In addition, there is no breakdown of the solution in the near-field as is often the case for techniques of traditional design utilizing polynomial basis functions, since the new theory uses no explicit basis to represent the current density.
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Title:: A case study on the application of the EMIGMA modelling package to Crone data over the SOQUEM Lac Volant Region, Sept-Îles, Québec, Extended Abstracts
By:: 1996. Parker, D.H, Boivin, M., Murray, I. R and Groom, R.W. 67th SEG Conference, Dallas, Texas.
Description:: This paper is part of an interpretation of Crone and Max-Min data collected at the Lac Volant property in Sept-Îles, Québec during the fall of 1996. Two conductive targets were delineated. It is shown that the use of electromagnetic modelling can enhance the comprehension of the relation between the data and the geological structure and so affect drilling decisions. In this case, the Lac Volant anomaly was determined to represent a spatially limited massive sulphide target despite the significant base metal values and the hope generated by the discovery.
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Title:: A case study of the application of the EMIGMA modelling package in interpretation of UTEM data over the Cominco Cerattepe deposit in Turkey, Extended Abstracts
By:: 1996. Groom, R.W., Hyde, C.H. and Lajoie, J. 66th SEG Conference, Denver, Colorado.
Description:: This paper is part of an interpretation of UTEM data collected at the Cerattepe property in northeastern Turkey during 1992 and 1993. Three exploration targets were delineated during the survey, namely the Cerattepe main zone, the Cerattepe north zone, and the Kardalen target. It is shown that the use of electromagnetic modelling can significantly enhance the comprehension of the relation between the data and the geological structure and so affect drilling decisions.
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Title:: Beyond the Born and Rytov Approximations: A Nonlinear Approach to Electromagnetic Scattering
By:: 1993. Habashy T. M, Groom, R.W. and Spies. B.R. J. Geophys Res., 98, no. B2, p. 1759-1775.
Description:: Four new, relatively simple nonlinear estimators presented in this paper can be used for rapid electromagnetic modeling in geophysical applications where conductivity can vary over many orders of magnitude. The first, the static localized nonlinear approximation, is designed specifically to correct the magnitude of the electric field internal to the scatterer. The second, the localized nonlinear approximation, improves the estimate of the phase of the scattered field and includes some of the cross-polarization effects due to full wave scattering. The third and the forth based on the Rytov transformation are designed to further improve the estimation of the phase of the scattered field, especially at high frequency and for larger size scatterers. The enhanced accuracy of the new estimators makes them potentially useful for the solution of low-frequency three-dimensional inverse problems in electromagnetics.
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