STRUCTURAL INTERPRETATION OF GRAVITY AND MAGNETIC ANOMALIES IN WINDOWS ENVIRONMENT
Software Sigma 3D was designed by a team of contributors: Y.I. Bloh, P.C. Babayants, A.A. Trusov.
Registered in Russian Patent &Trade Mark Office (ROSPATENT) on January 11, 2001. Patent License # 2001610014
A list of main users:
- GNPP Aerogeophysica
- PANGUEYA Inc.
- Gravirazvedka Inc.
- ALROSA Ltd.
- Research institute GeoInformSystem
- Aerogeophysica-Latin America (Brazil)
Over the last 5 years the data interpretation software SIGMA 3D helped to interpret gravity and magnetic data for over 20% of the territory of Russia.
The software includes six modules:
- ROMGAS – evaluation of sub-horizontal formation boundary morphology;
- REIST – automatic gravy and magnetic field modeling;
- DVOP – computing of volume distribution of effective parameters (density and magnetism);
- CLASS2 – interactive classification of double-parameter spatially-distributed data;
- OPRES – identification of anomalies with given shapes (including complex anomalies);
- QUASI – quantitative interpretation of magnetic anomalies through the method of quasiequivalent solution retrieval.
The software is used to perform various geological assignments:
- Structural and compositional mapping and study of internal structure of metamorphic basement of platforms.
- Separation of anomalous fields from basement and sedimentary sheath influence.
- Research into deep structure of the Earth crust along regional geotraverses.
- Search for geological bodies with given properties.
- Discovery and mapping of prospective oil and gas deposit structures within sedimentary sheath based on multipole approach.
- Detection and quantitative description of pipe-shaped bodies, including kimberlites and uranium bodies etc.
Basic software design principles:
- For interpretation of fields, it’s necessary to use the prestack data received in actual observation points based on all three coordinates. It does not exclude the possibility of data representation in terms of matrices (at grid-points in the horizontal plane) although this type of representation can be only auxiliary.
- The volume of primary data (the scale of assignment) is limited only by the features of the computer.
- On the one hand the technology built into the software package must be able to take into account all the prior geophysical data, but on the other hand it must be able to continue operating in complete absence of such data.
- Informative geological interpretation (including integrated interpretation) of physical fields must be performed primarily through the analysis of the parameterized models constructed on the basis of the fields, that is spatial distribution of physical properties.
- When analyzing and separating potential fields, it is necessary to use sourcewise approximations. The main advantage of such approach is an opportunity to perform sequential reduction of the source field by excluding the components, which appeared under the influence of bodies with specified properties. It is especially relevant when working in the areas whose geological structure is represented by two structural levels (this situation is very common in prospective oil and gas bearing regions). In this case even if the starting model contains errors, the reduced (residual) field retains sourcewiseness, and the whole spectrum of available methods, including quantitative ones, can be used for the interpretation.