3D Litho-Prediction Model from In-Situ Physical Rock Property Logging and Constrained Potential Fields Data Inversion.

Gervais Perron and P. Fullagar and Glenn Pears and N. Phillips and C. Williston and V. Gerrie and J. Everest. ( 2011 )
in: Proc. 31st Gocad Meeting, Nancy

Abstract

Geologically constrained geophysical data inversions are used to derive 3D petrophysical models that are consistent with measured geophysical field components at the surface and existing geological knowledge. As these petrophysical models are expressed in physical rock properties units or contrasts, their direct interpretation from a lithological standpoint is often ambiguous. Lithological unit characterization of in-situ petrophysical logging is used to define physical rock property profiles for each rock type within an exploration volume, in order to establish statistical quantitative relationships between geophysical inversion results and geological rock identification done by geologists. Based on those profiles and the constrained inversion results, it is possible to generate 3D litho-prediction models, along with associated uncertainty and ambiguity parameters, by computing normalized distances between a plot point in multi-dimensional physical rock property space and the two closest cluster centers representing lithological distributions in this space. GOCAD is the multi-disciplinary data integration software platform used for this process. From the initial 3D geological model to producing constraints for the potential field data inversions and establishing the link with the litho-prediction software (LogTrans), GOCAD’s adaptable data model and advanced visualization makes it the ideal software for this type of work. Case study results of applying this method to copper-nickel-precious metal exploration in the vicinity of the Sudbury Igneous Complex in Canada demonstrate how, by combining downhole in-situ physical rock property logging data and potential fields (gravity and magnetic) data inversions, it is possible to produce a full 3D litho-prediction model that can be used by mining companies to vector towards new prospective ground. In the case of the Victoria property, Quadra FNX Mining Ltd. (Quadra FNX) has used this process to help identify lithologies at depth, including quartz diorite, a key marker unit for exploration.

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BibTeX Reference

@inproceedings{PerronGM2011,
 abstract = { Geologically constrained geophysical data inversions are used to derive 3D petrophysical models that are consistent with measured geophysical field components at the surface and existing geological knowledge. As these petrophysical models are expressed in physical rock properties units or contrasts, their direct interpretation from a lithological standpoint is often ambiguous. Lithological unit characterization of in-situ petrophysical logging is used to define physical rock property profiles for each rock type within an exploration volume, in order to establish statistical quantitative relationships between geophysical inversion results and geological rock identification done by geologists. Based on those profiles and the constrained inversion results, it is possible to generate 3D litho-prediction models, along with associated uncertainty and ambiguity parameters, by computing normalized distances between a plot point in multi-dimensional physical rock property space and the two closest cluster centers representing lithological distributions in this space.
GOCAD is the multi-disciplinary data integration software platform used for this process. From the initial 3D geological model to producing constraints for the potential field data inversions and establishing the link with the litho-prediction software (LogTrans), GOCAD’s adaptable data model and advanced visualization makes it the ideal software for this type of work.
Case study results of applying this method to copper-nickel-precious metal exploration in the vicinity of the Sudbury Igneous Complex in Canada demonstrate how, by combining downhole in-situ physical rock property logging data and potential fields (gravity and magnetic) data inversions, it is possible to produce a full 3D litho-prediction model that can be used by mining companies to vector towards new prospective ground. In the case of the Victoria property, Quadra FNX Mining Ltd. (Quadra FNX) has used this process to help identify lithologies at depth, including quartz diorite, a key marker unit for exploration. },
 author = { Perron, Gervais AND Fullagar, P. AND Pears, Glenn AND Phillips, N. AND Williston, C. AND Gerrie, V. AND Everest, J. },
 booktitle = { Proc. 31st Gocad Meeting, Nancy },
 title = { 3D Litho-Prediction Model from In-Situ Physical Rock Property Logging and Constrained Potential Fields Data Inversion. },
 year = { 2011 }
}