Seismic depth imaging of sequence boundaries beneath the New Jersey shelf
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ORIGINAL RESEARCH PAPER
Seismic depth imaging of sequence boundaries beneath the New Jersey shelf M. Riedel1 · S. Reiche2 · K. Aßhoff2,3 · S. Buske3 Received: 21 December 2017 / Accepted: 31 May 2018 © Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract Numerical modelling of fluid flow and transport processes relies on a well-constrained geological model, which is usually provided by seismic reflection surveys. In the New Jersey shelf area a large number of 2D seismic profiles provide an extensive database for constructing a reliable geological model. However, for the purpose of modelling groundwater flow, the seismic data need to be depth-converted which is usually accomplished using complementary data from borehole logs. Due to the limited availability of such data in the New Jersey shelf, we propose a two-stage processing strategy with particular emphasis on reflection tomography and pre-stack depth imaging. We apply this workflow to a seismic section crossing the entire New Jersey shelf. Due to the tomography-based velocity modelling, the processing flow does not depend on the availability of borehole logging data. Nonetheless, we validate our results by comparing the migrated depths of selected geological horizons to borehole core data from the IODP expedition 313 drill sites, located at three positions along our seismic line. The comparison yields that in the top 450 m of the migrated section, most of the selected reflectors were positioned with an accuracy close to the seismic resolution limit (≈ 4 m) for that data. For deeper layers the accuracy still remains within one seismic wavelength for the majority of the tested horizons. These results demonstrate that the processed seismic data provide a reliable basis for constructing a hydrogeological model. Furthermore, the proposed workflow can be applied to other seismic profiles in the New Jersey shelf, which will lead to an even better constrained model. Keywords Seismic imaging · Velocity modelling · Reflection tomography · Groundwater modelling
Introduction Subsurface flow and transport processes are often studied via numerical simulations (Clauser 2003; Anderson et al. 2015). The basis for simulating such processes in a realistic way is usually a well-constrained geological model. Much of the information incorporated into geological models is based on geophysical data with seismic reflection profiles representing one of the most widely used and informative * M. Riedel [email protected] 1
Department of Geosciences and Geography, University of Helsinki, P.O. Box 68, 00014 Helsinki, Finland
2
Institute for Applied Geophysics and Geothermal Energy, RWTH Aachen University, Mathieustraße 10, 52074 Aachen, Germany
3
Institute of Geophysics and Geoinformatics, Technische Universität Bergakademie Freiberg, Gustav‑Zeuner‑Straße 12, 09596 Freiberg, Germany
sources. Ideally, seismic data provide reliable information on the shape and depth of lithological boundaries. However, the quality of such information is strong
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