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Using Supervirtual First Arrivals for Improving the Seismic Imaging of Deep Deposits - Well Worth the Effort
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, EAGE/DGG Workshop on Deep Mineral Exploration, Mar 2016, Volume 2016, p.1 - 5
Abstract
Different applications of seismic interferometry have arisen in the last decade, however the potential of this technique to improve reflection seismic processing in hardrock environments has not been regarded explicitly. Therefore, in this paper we investigate the potential of retrieving the first arrivals originally hindered by high noise level in the exploitation of controlled-source data acquired over the apatite-iron deposit at Grängesberg (Sweden) and its mining-induced structures. The supervirtual first arrivals generated using interferometry methodologies allowed first-breaks to be picked more extensively than in the original data. Revised static corrections significantly improved the linearity of the first arrivals and continuity of reflections in the source gathers. Especially, reflections considerably enhanced in the source gathers stacked constructively in the final seismic section. Comparison with geologic data, supported by reflection-traveltime forward modelling, indicates that these reflections represent the deep (> 700 m) and unmined part of the deposit. Other reflections at shallower depth are interpreted as anthropogenic faults possibly located at lithological contacts (pegmatites). Even though the potential of first-arrivals retrieval is likely case-dependent, this study illustrates that interferometry may substantially improve the accuracy of field static corrections and subsequent stack for hardrock imaging and deep mineral exploration.