Projekteja vuodessa
Abstrakti
The focus of this study is reflection seismic imaging of a massive sulfide ore deposit in the Kylylahti Cu-Au-Zn mine in eastern Finland. The geological environment in the target area is dominated by high-velocity rocks which have been severely folded resulting in a complicated assemblage of various near-vertical structures. In order to image those, we rely on VSP data that were acquired in the Kylylahti mine using conventional three-component geophones in four boreholes as well as a fiber-optic Distributed Acoustic Sensing (DAS) cable in one borehole. The boreholes were located within a few hundreds of meters from the known ore body. The use of high-frequency VSP systems directly within the mine is a fortunate situation which enables very good spatial resolution. Despite this, the processing and interpretation of the acquired data is not straightforward due to the geological complexity of the area. Elastic three-dimensional full-waveform seismic modeling was conducted in order to facilitate the understanding of the acquired data. For this purpose, a realistic geological model of the environment was constructed based on extensive borehole data and petrophysical laboratory measurements. Using this model in combination with the true acquisition geometry, a synthetic dataset was generated which is a very close representation of the acquired field data. Based on the synthetics, target reflection signatures were traced to their geological origins and then linked to similar features in the acquired field data. Both datasets were processed in the same way and then migrated in order to map the recorded reflections in 3D space. The resulting reflectivity sections show the ore signature, as well as other dominant lithological contrasts, with high spatial accuracy. We conclude that the applied conventional and DAS VSP methodologies provide sufficient spatial accuracy to correctly image the sub-vertical ore deposit. However, in order to confidently interpret the acquired data in such a challenging environment, realistic synthetic modeling is required to understand the recorded signals with respect to their geological origins.
Alkuperäiskieli | englanti |
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Otsikko | Proceedings of Exploration ’17 : Seismic Methods & Exploration Workshop |
Toimittajat | G. Bellefleur, B. Milkereit |
Sivumäärä | 7 |
Kustantaja | Decennial Mineral Exploration Conferences |
Julkaisupäivä | lokak. 2017 |
Sivut | 57-63 |
Artikkeli no | Paper 10 |
Tila | Julkaistu - lokak. 2017 |
OKM-julkaisutyyppi | D3 Artikkeli ammatillisessa konferenssijulkaisussa |
Tapahtuma | Exploration - Toronto, Kanada Kesto: 21 lokak. 2017 → 25 lokak. 2017 |
Tieteenalat
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Projektit
- 1 Päättynyt
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COGITO-MIN: COst-effective Geophysical Imaging Techniques for supporting Ongoing MINeral exploration in Europe
Koivisto, E. (Projektinjohtaja), Komminaho, K. (Osallistuja), Riedel, M. (Osallistuja), Luhta, T. (Osallistuja), Väkevä, S. (Osallistuja), Junno, N. (Osallistuja), Heikkinen, P. (Osallistuja) & Kukkonen, I. (Osallistuja)
01/01/2016 → 31/12/2018
Projekti: Tutkimusprojekti