The survey was initiated by Professor Siyan Malomo, Director General of the NGSA, and it was conducted in two phases. Phase 1 was financed entirely by the Government of Nigeria. All of the airborne geophysical work – data acquisition, processing and interpretation, was carried out by Fugro Airborne Surveys. Phase 1 was completed in September 2007 and included 826,000 line-km of magnetic and radiometric surveys flown at 500 m line spacing and 80 m terrain clearance; and 24,000 line-km of time-domain electromagnetics surveys flown at 500 m line spacing and 80 m terrain clearance using the TEM PEST system. Phase 2, completed August 2009, surveyed blocks not covered in Phase 1. It included 1,104,000 line-km of magnetic and radiometric surveys flown at 500 m line spacing and 80 m terrain clearance. These levels of survey are intensive: often a total of seven aircraft of three different types were active at one time.

Some details and maps in the presentation:

http://www.mmsd.gov.ng/Downloads/Fugro_Phase_1_Nigeria_Interpretation_Presentation.pdf

SEG invites papers on the topic of “Hydrogeophysics — Electric and Electromagnetic Methods” for publication in the July-August 2010 special section or supplement of Geophysics.

“Hydrogeophysics is a rapidly evolving discipline of geophysical methods dedicated to revealing properties and monitoring processes in the vadose zone as well as in aquifers. The discipline is relevant for environmental, hydrological, and agricultural research and engineering. Key processes in the application areas are contaminant transport, sustainability of ecosystems and biodiversity, plant growth, and soil-atmosphere interactions. Groundwater is the key component in the subsurface pore volume, for which reason electric and electromagnetic methods are most suitable for addressing the problems related to shallow subsurface spatial and temporal variability, its inaccessibility, which hinders the observation of relevant processes, and its role in connecting atmosphere, surface, and groundwater/reservoirs.

For this topic, Geophysics invites papers describing the theory, application, and benefits of advanced methods of hydrogeophysics. The application scale may range from the pore scale to the field scale involving more than 1 hectare of surface area. In particular we welcome techniques that exploit the evolution of new passive and active electric and electromagnetic acquisition strategies and advanced data processing and inversion schemes that show an increase in computational speed. Finally, we also encourage papers that highlight case studies and thereby emphasize the practical aspects and illustrate the potential pitfalls, problems, and limitations of the applied techniques.”

http://www.publish.csiro.au/?act=view_file&file_id=EGv41n1toc.pdf

SEG eBooks beta launched in early February 2010 with approximately 35 books, and SEG plans to add 15 more titles within two months. SEG will add new books online as they are published in print and plans to add legacy titles in the years ahead.

SEG eBooks content is searchable via its own search engine or with those covering the SEG Digital Library and Scitation. Browsing is available by title, year, series, and topic. Introductory material and back matter (mostly indexes and references) are free.

QUEST-South Project in British Columbia includes a new airborne gravity survey (Sander Geophysics) which covers 45,000 square kilometers between Williams Lake and the USA border. The airborne gravity digital data, grids and final technical report can be downloaded at Geoscience BC QUEST Project Data Releases.  This gravity survey involved more than 25,000 line kilometeres of data at a 2 km line spacing.

Mapping reservoirs based on resistivity and induced polarization derived from continuous 3D magnetotelluric profiling: Case study from Qaidam basin, China

Zhanxiang He,¹ Zuzhi Hu,¹ Weifeng Luo,¹ and Caifu Wang^1
1China National Petroleum Corporation, GME department BGP, Zhuozhou, China.

In Sanfu, Qaidam basin, China, traditional geophysical methods have failed to find subtle hydrocarbon reservoirs. In an attempt to predict anddelineate gas reservoirs, we used a type of magnetotelluric (MT) profiling called 3D continuous electromagnetic profiling (CEMP). Electric logs indicate that gas-bearing formations have high resistivity relative to nongas-bearing formations.

Modeling and analysis of the response of a triaxial, frequency-domain electromagnetic induction sensor to a buried linear conductor

Sean P. McKenna¹ and Jason R. McKenna^2
1Northrop Grumman Information Systems, Andover, Massachusetts, U.S.A.
²U. S. Army Engineer Research and Development Center, Vicksburg, Mississippi, U.S.A.l

This paper presents analytical modeling results for a triaxial frequency-domain electromagnetic-induction (EMI) sensor over a homogeneous earth containing a long linear conductor. Although the conductor studied is intended to represent an underground wire or pipe, it can represent any subsurface, linear geologic structure that can channel current.

Comprehensive approaches to 3D inversion of magnetic data affected by remanent magnetization

Yaoguo Li,¹ Sarah E. Shearer,²

¹Colorado School of Mines, Center for Gravity, Electrical, and Magnetic Studies (CGEM), Department of Geophysics, Golden, Colorado, U.S.A.
²Formerly Colorado School of Mines, Center for Gravity, Electrical, and Magnetic Studies (CGEM), Department of Geophysics, Golden, Colorado, U.S.A. Presently Ultra Petroleum Corp., Denver, Colorado, U.S.A. E-mail:

Three-dimensional (3D) inversion of magnetic data to recover a distribution of magnetic susceptibility has been successfully used for mineral exploration during the last decade. However, the unknown direction of magnetization has limited the use of this technique when significant remanence is present. We have developed a comprehensive methodology for solving this problem by examining two classes of approaches and have formulated a suite of methods of practical utility.

Leveling HEM and aeromagnetic data using differential polynomial fitting

Majid Beiki,¹ Mehrdad Bastani,¹ and Laust B. Pedersen^1
1Uppsala University, Department of Earth Sciences, Geophysics, Uppsala, Sweden.

We introduce a new technique to level aerogeophysical data. Our approach is applicable to flight-line data without any need for tie-linemeasurements. The technique is based on polynomial fitting of datapoints in 1D and 2D sliding windows. A polynomial is fitted to data points in a 2D circular window that contains at least three flight lines.

Extraction of structure-based geoelectric models by hybrid genetic algorithms

Irfan Akça¹ and Ahmet Tuğrul Basokur^1
1Ankara University, Faculty of Engineering, Department of Geophysical Engineering, Tandogan Kampusu, Ankara, Turkey.

A major difficulty in electrical resistivity imaging is the identification ofthe lithologic units, especially in the sedimentary environments. The geologic interpretation generally is realized by visual inspection of the final resistivity section. Although sharp boundary inversion techniques based on a local linearization could allow the delineation of interfaces between geologic units, these techniques will succeed only if an initial model already close to the best solution is available.

The Misadventures of Interpreter Sam (SEG Geophysical Monograph Series No. 15) is a collection of the first six years of “Interpreter Sam” columns from THE LEADING EDGE. It contains commentary on both the humorous and serious sides of an interpreter’s day from the point of view of the fictitious Interpreter Sam, our Everyman of interpretation. Sam introduces each chapter with a caricature of himself (an interpretation of his own “reflection,” if you will, created by the talented artist David Carman), and in the epilogue, he offers a special gift to his friends in data processing. This book can be read and enjoyed by anyone who has ever interpreted even a single seismic line, by eager students who aspire to be interpreters, and by nongeoscientists who presume that they know how interpreters think.

Florent Sourbier, Stephane Operto, and others. Geosciences Azur, France. FWT2D: A massively parallel program for frequency-domain full-waveform tomography of wide-aperture seismic data—Part1 Algorithm. Computers & Geosciences 35 (2009) 487–495.

FWT2D: A massively parallel program for frequency-domain full-waveform tomography of wide-aperture seismic data Part 2 – Numerical example sand scalability analysis. Computers & Geosciences 35 (2009) 496–514.

Magdel Combrinck. University of Pretoria, South Africa. Analysis of numerical differentiation methods applied to time domain electromagnetic (TDEM) geophysical data in the S-layer differential transform. Computers & Geosciences 35 (2009) 1563–1573.

Igor Morozov, Glenn Chubak, Shannon Blyth. Department of Geological Sciences, University of Saskatchewan. Interactive 3D/2D visualization for geophysical data processing and interpretation. Computers & Geosciences 35 (2009) 1397–1408.

G.R.J. Cooper. School of Geosciences, University of the Witwatersrand, Johannesburg 2050, South Africa. The antialiased textural analysis of aeromagnetic data. Computers & Geosciences 35 (2009) 586–591.

Ahmad Ghorbani, Christian Camerlynck, Nicolas Florsch, Universite Pierre et Marie Curie, Paris, France, Paris and Department of Mathematics and Applied Mathematics, Cape Town University, South Africa. CR1Dinv: A Matlab program to invert 1D spectral induced polarization data for the Cole–Cole model including electromagnetic effects. Computers & Geosciences 35 (2009) 255–266.

K. Prabhakar Rao, G.Ashok Babu. National Geophysical Research Institute, Hyderabad, India. Microsoft C#.NET program and electromagnetic depth sounding for large loop source. Computers & Geosciences 35 (2009) 1369–1378.

OliverBaur. Institute of Geodesy, Universita¨t Stuttgart, Germany. Tailored least-squares solvers implementation for high-performance gravity field research. Computers & Geosciences 35 (2009) 548–556.

Seong KonLee, Hee Joon Kim, Yoonho Song, Choon-KiLee. Korea Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea, Pukyong NationalUniversity,Republic of Korea. MT2DInvMatlab—A program in MATLAB and FORTRAN for two-dimensional magnetotelluric inversion. Computers & Geosciences 35 (2009) 1722–1734.

Franz Kohlbeck, Dana Mawlood. Institute of Geodesy and Geophysics, Vienna University of Technology, Austria, Department of Civil Engineering, College of Engineering, University of Salahaddin, Erbil, Iraq . Computer program to calculate resistivities and layer thicknesses from Schlumberger soundings at the surface, at lake bottom and with two electrodes down in the subsurface. Computers & Geosciences 35 (2009) 1748–1751.

I. Bifulco, G.Raiconi, R.Scarpa Universita’degli Studidi Salerno, Dipartimentodi Matematicae Informatica, Fisciano,SA,Italy. Computer algebra software for least squares and total least norm inversion of geophysical models. Computers & Geosciences 35 (2009)

Exploration Geophysics, Gadallah, Mamdouh R., Fisher, Ray.

Many text books have been written on the subject “Exploration Geophysics”. The majority of these texts focus on the theory and the mathematical treatment of the subject matter but lack treatment of practical aspects of geophysical exploration. This text is written in simple English to explain the physical meaning of jargon, or terms used in the industry. It describes how seismic data is acquired in 2-D and 3-D, how they are processed to convert the raw data to seismic vertical and horizontal cross sections, that are geologically meaningful, and how these and other data are interpreted to delineate a prospect. Workshops are included after each chapter and are designed to reinforce learning of the concepts presented.

Groundwater Geophysics. A Tool for Hydrogeology. Kirsch, Reinhard (Ed.).

Geophysical techniques can map the underground conditions apart from boreholes. The use of these methods for hydrogeological applications is demonstrated for mapping of porous aquifers, mapping of structural aquifers, determintation of groundwater quality (mineralization), geophysical assessment of hydraulic properties, determination of aquifer vulnerability, and mapping of comtaminated sites. Additionally, a description of applied geophysical techniques used for groundwater studies is given including seismics, resistivity methods, magnetics, and ground penetrating radar. Even advanced techniques like NMR (nuclear magnetic resonance) are presented.

Principles of the Magnetic Methods in Geophysics Volume 42. By Alex A. Kaufman, Richard O. Hansen and Robert L. Kleinberg

Covers all the physical and mathematical principles of magnetic methods regardless of the area of application and  presents thorough developments of magnetic methods.

Geophysical Electromagnetic Theory and Methods Volume 43. Michael S. Zhdanov

In this book the author presents the state-of-the-art electromagnetic (EM) theories and methods employed in EM geophysical exploration.
The book brings together the fundamental theory of EM fields and the practical aspects of EM exploration for mineral and energy resources.
This text is unique in its breadth and completeness in providing an overview of EM geophysical exploration technology.