As a service to our sponsors, and to the community in general, we organize workshops on topics in potential fields that have been advanced by CGEM and are of broad interest in industry. The workshops feature CGEM speakers as well as guest speakers from around the world. These workshops provide a forum for us to present latest CGEM research results, introduce new methodologies to the potential-field community, and for potential-field geophysicists to interact with each other. To encourage students' interest in potential-field methods, we always welcome students to attend the workshops free of charge.

April 19-22, 2015: Gravity, electrical & magnetic methods and their applications (GEM Chengdu 2015)

GEM Beijing 2011 was a successful workshop that attracted participants from different countries and provided excellent networking opportunities for geophysicists from different continents. The goal of GEM Chengdu 2015 is again to bring together experts from academia, government agencies, resources companies, and contractors to share the latest technological and methodological developments and successful experiences, and to discuss challenges and future directions and needs. Gravity, electrical, electromagnetic, magnetic, and nuclear magnetic resonance methods are among the primary tools for exploring natural resources (oil and gas, minerals, geothermal) as well as for tackling geotechnical and environmental problems. Sensors, tools, acquisition techniques, processing and interpretation methods are common among these different applications. This Workshop covers the technologies and methodologies, brings a suite of applications to a common forum, so that we can enjoy and learn from related applications of the same technologies.

February 14, 2015: Gravity gradiometry and magnetic data with remanence: processing, inversion, and interpretation (ASEG-PESA 2015)

The workshop will focus on the processing, inversion, and interpretation of gravity gradient data and magnetic data affected by remanence. We begin with a review of the mathematical foundation for both gravity gradient and magnetic data and the theoretical connection between the two potential fields. The connection enables us to make use of the understanding and common data processing and qualitative interpretation techniques that have been available in the potential-field community for decades. Topics that cover both potential-field methods include equivalent source processing and source parameter estimation techniques. For gravity gradient data, we will discuss practical aspects of both processing and inversion. Focusing on magnetic data with remanent magnetization, we discuss estimation of magnetization direction and the utility of amplitude data. Finally, we discuss amplitude inversion and magnetization vector inversion to overcome the difficulties of interpreting.

November, 2014: Processing and inversion of airborne gravity gradiometry (SEG 2014 Shortcourse)

Airborne gravity gradiometry has become an important and unique tool of modern geophysical exploration in mineral and petroleum explorations. The method is also expanding into other geo-scientific areas such as groundwater investigations and crustal studies. With the increased data acquisition and applications over the last decade, a suite of methods has been developed for the processing and interpretation of these data. This short course aims to provide an overview of gravity gradiometry, to introduce the theoretical bases of the processing and inversion algorithms, and to discuss practical issues in the application of these data. We will begin with an introduction to the basic principles of modern gravity gradiometry and the mathematical foundation of gravity gradients. We will next discuss the theoretical connection between the gravity gradiomerty data with the traditional gravity and magnetic data in applied geophysics. The connection enables us to make full use of intuitive understanding and common data processing and qualitative interpretation techniques that are available in the potential-field community for decades. We will then discuss three major aspects in quantitative interpretation of modern gravity gradient data: (1) theoretical and practical considerations and efficient numerical algorithms for terrain corrections; (2) de-noising and signal enhancement of multi-component gravity gradiometry data using wavelet transform and equivalent source techniques; and (3) inversion of gravity gradient data to recover 3D distributions of density in the subsurface. The short course will use both synthetic examples and field cases in mineral and petroleum exploration to illustrate the theory, algorithms, and interpretation methodologies. Attendees are encouraged to bring a laptop computer to interactively participate in hands-on demonstrations of the processing and interpretation techniques.

October 26, 2014: Potential-Field Interpretation Workship: Recent acvances in interpretation techniques for potential-fields

The Workshop will focus on magnetic data and integrated interpretation techniques in combination with gravity gradiometry. We will cover basement characterization techniques including depth estimation and use of magnetic amplitude data in the presence of strong remanent magnetization. Interpretation of magnetic data from difficult environments, where the assumption of only induced magnetization no longer holds true, will be addressed through estimation of magnetization direction and different inversion approaches. Application of these techniques in the presence of strong self-demagnetization will also be discussed. Case studies illustrating interpretation techniques will be given throughout the workshop.

October 21, 2010: SEG Workshop on: Gravity and Magnetic Techonologies Applied to Drilling, Development, and Production [presentation only, workshop not organized by CGEM]

This presentation demonstrates a modern approach to high-quality feasibility studies using two field site examples. The frist is a representation of the Jotun Field in the Norwegian North Sea based on early production history, and the second is the Delhi Field in Louisiana for CO2-EOR Process. We demonstrate reservoir model construction from available prior information, application of binary inversion technology tailored specifically to these time-lapse gravity problems, and the level of added information recoverable on fluid movement by joint interpretation of surface and borehold data. Lastly, this presentation illustrates a method of resolution analysis to demonstrate the decreased recoverablility of fluid movement at a site in the presence of varying noise limits in the data. This multi-stage workflow demonstrates a reliable approach to understanding the applications and limitations of 4D gravity at a particular site, for both pre-acquisition feasibility studies and as a guide for post-data acquisition interpretation.

September 27, 2007: SEG Workshop on 4D Gravity Monitoring of Reservoirs and Aquifers (pdf)

This workshop focussed on recent advances in gravimeter technology and the emerging need for characterizing the dynamic changes of subsurface systems have led to increased application of microgravity method in time-lapsed monitoring, also known as 4D gravity. Various groups have applied 4D gravity to ground water aquifers of small scales to large oil and gas reservoirs with noticeable success. However, specifics of the technology are still being developed and data sets are rarities. Huge potential in both research and application lies ahead. This workshop aims to bring together the researchers, practitioners, and users of 4D gravity from academia and ground water and petroleum industries to present and discuss the emerging technology. The goal is to provide a forum for presentation of the state-of-art of instrumentation, field survey methods, and data interpretation. With this backdrop, the workshop hopes to facilitate the interaction between different groups and foster rigorous discussion on the future direction of the technology.

July 26, 2002: Workshop on Automatic Depth Estimation Techniques in Potential Fields

This workshop focussed on the automatic depth estimation techniques in potential-field methods. This is a class of techniques that can rapidly process large data sets and provide first-order information about the source depth. The presentations at the workshop include overviews on depth estimation, traditionally available methods, as well as the newly developed Extended Euler deconvolution. The Proceedings CD is currently available for distribution.

October 27, 2000: Application of Wavelets in Potential Fields: A Global Virtual Workshop.

This was the first workshop presented by GMRC. The theme was on the application of wavelets in potential fields. We organized the workshop to provide participants with basic background on wavelet transforms and then focussed on three major areas of application:

  1. Data filtering based using wavelets,
  2. Fast numerical algorithms using wavelet compression, and
  3. Interpretation techniques using natural wavelets.

This was a virtual workshop that featured seven speakers from four countries including Australia, France, and United States. The entire workshop was broadcast via Internet to eleven sites in five countries that hosted over 100 participants. The Proceedings CD is currently available for distribution.