AAPG Middle East Region Geoscience Technology Workshop, Rift Basin Evolution and Exploration

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Seismic Imaging and Model Building in Complex Rift Geology

Abstract

It is well known that the geology of rift basins may be highly complex, with complicated faulting and inversions. In the presence of significant associated volcanic activity and salt tectonics, such a setting will prove a major challenge to seismic model building and imaging. The solution to these challenges will need to be able to resolve interleaved three-dimensional geo-bodies with high impedance contrasts in near-surface settings as well as deal with numerous fault systems (and associated fault-shadows). In this paper, we will illustrate, with relevant examples, how the move towards so-called ‘closed looped’ imaging solutions may be helpful in determining geological structure in complex rift settings. Closed loop imaging solutions are an emerging technology that merge the imaging and model-building sections of a traditional seismic imaging project in an attempt to find the optimal solution for both the seismic image and earth properties model (e.g. Brittan and Jones, 2019). Typically, this involves both a form of full-waveform inversion and least-squares migration. Full-waveform inversion has evolved from a monolithic approach to a tool-kit of algorithm variants, which enhance its applicability in a wide variety of geological settings (both land and offshore, in various water depths). It has been shown, for instance, that an extended parameter full-waveform inversion can be highly effective in recovering complex Nile Delta Messinian salt-structure (Fruehn et al., 2019) and that such solutions are highly relevant in such areas as the Red Sea (Brittan et al., 2018). References Brittan, J., and Jones, I.F, 2019, FWI evolution – from a monolith to a toolkit, The Leading Edge, 38, no.3, 179-184. Brittan, J., Jones, I., Farmer, P., Wang, C. and Calderon, C., 2018. Optimising our understanding of the subsurface by application of a suite of full waveform inversion algorithms in complex media. Presented at the SEG Red Sea Workshop, Hurghada, Egypt. Fruehn, J., Greenwood, S., McDermott, K., Mannick, S. and Wang, C., 2019. Recovering Nile Delta Messenian salt structure using Reconstructed Full Waveform Inversion. Extended Abstracts for the EAGE Conference and Exhibition.