SOFTWARE

One emphasis of CGEM is technology transfer. Besides the usual approach of providing our sponsors with annual reports and detailed technical reports on different projects, we are committed to delivering one program package each year. The objective is to transfer the technologies resulted from research back to our sponsors for practical applications.

These packages are not the typical research programs. Instead, we take the codes generated from the research phase and further develop them into near commercial quality softwares that are fully tested and documented (FORTAN). The included Graphic User Interface (GUI) enables these delivered programs to be used directly in active exploration projects without the need to integrate them into sponsors' existing softwares. Brief descriptions of these packages are provided below.

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Major Applications:
CGEMaestro
GG3D- Gravity Gradiometry Inversion
GSURFINV- Gravity Inversion with Surfaces
BININV3D- Binary Inversion of Gravity Data
AMPINV3D- Magnetic Amplitude Inversion

Minor Utility Applications:
GG_Terrain
Gz_Terrain
GGFOR3D
Plot Tenser
GXF2GXF
GXF Utility
Level
AMPFOR3D
GSURFFOR
Terrace:updated magnetic terracing
MAGAMP: convert total field to amplitude
Plot / Grid- newly developed utility for gridding and generation of high quality data image

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CGEMaestro: A software package developed at the Center for Gravity, Electrical & Magnetic Studies (CGEM) for the sponsors of the Gravity and Magnetics Research Consortium (GMRC)

Members of Center for Gravity, Electrical & Magnetic Studies (CGEM) have begun development of an in-depth, multi-year software package in large for the sponsors of the Gravity and Magnetics Research Consortium (GMRC). The package, named CGEMaestro, is designed to bring all of the programs developed over the past, present and future together through a simple and elegant interface. This algorithm will allow the user to perform numerous operations related to the processing and interpretation of gravity and magnetic data. In addition, the project will likewise standardize all existing and future algorithms such that data and model formatting are consistent from component to component. While significant progress has already been made towards a deliverable package, the long term development of component links to CGEMaestro may occur through the requests and recommendations of the sponsoring companies directly. In this presentation, we demonstrate the current state of the software package, including current research code already built into the program, additions which we have already begun to develop for the future, and possible additions of interest to the GMRC sponsors.




Binary Inversion v2.1 (BININV3D)

The algorithm, developed at the Gravity and Magnetics Research Consortium, is a tool for inverting gravity over a 3 dimensional distribution of density contrast, or anomalous density (henceforth referred to as ’density’ for simplicity). The program is based on the binary formulation presented in the publications: Krahenbuhl & Li (2006) and Krahenbuhl (2005). For the salt body problem, the method is well suited for overcoming difficulties which arise when the salt body straddles a nil-zone – i.e. a region where there is no density contrast between salt and sediment. The binary inverse approach has likewise proven valuable for the time-lapse gravity inverse problem, where there is a well defined subsurface density change due to fluid flow over time.



Gravity gradient forward modeling (GGFRQFWD)

Developed by the Gravity and Magnetics Research Consortium to study the effect of terrain resolution on the accuracy of complete Bouguer corrections in the presence of acquisition filters in airborne gravity gradiometry surveys, the algorithm proved efficient for large-scale modeling of density contrasts. Gravity gradient data are useful in structural basin characterization in petroleum and mining applications, and for direct detection of dense ore bodies, to name a few. The data are high quality relative to other airborne survey types due to the rejection of common mode noise, the direct measurement of quantities that are calculated from noisy data in standard gravity surveys, and the collection of redundant data. Utilizing the Frequency domain, the program will work up to six orders-of-magnitude faster than a cell-based spatial domain approach and is useful to model any density variation that can be represented as a layer. Several layers can be superimposed to model the gravity gradient response due to realistic geology.


TERRACE


The terracing program, developed by the is an implementation of the technique proposed by Lindrith Cordell and A. E. McCafferty in "A terracing operator for physical property mapping with potential field data" published in GEOPHYSICS, 1989, vol. 54, No. 5, pages 621 – 634. The only departure from the proposed technique is that this version of the program uses a modified approach to curvature determinations, by using the value of the curvature in the direction of maximum gradient. The terracing is achieved through an iterative process.

GGDNS: A Program Library for Estimating and Removing Noise from Gravity Gradiometry Data

GGDNS is a program libary designed to estimate and remove the noise contaminating gravity gradiometry data. The automatic denoising algorithm utilizes the discrete wavelet transform based on orhtonormal, compactly supported wavelets such as Daubechies wavelets or symmlets. It operates on data profiles so that the noise in data can be removed before they are gridded for subsequent processing and interpretation.


EEDECON: A Program Library for Performing Extended Euler Deconvolution of Magnetic Data

EEDECON estimates the depth to source based on Extended Euler deconvolution of magnetic data. There are two main variants of this program. In the first variant, the structural index (SI) is specified and the program solves for source location (x0 , y0 , and z0) and background values. In the second variant, the SI is also considered as an unknown and the program solves simultaneously for it together with the source location. The GUI allows the user to easily input a grid file in GXF format, specify an output file, and select an Extended Euler deconvolution method with parameters. It then automatically calculates derivatives and the generalized Hilbert transform, and carries out Euler deconvolution.

GG3D: A Program Library for 3D Inversion of Gravity Gradiometry Data

This program inverts for density contrast distribution from multi-component gravity gradiometry data. The program has the capability to impose lower and upper bounds on the inverted density contrast. It also allows arbitrary data locations for maximum flexibility. We have also incoporated wavelet compression to speed up the inversion and increase the size of the problems that can be solved.