3D seismic analysis of buried tunnel valleys in the Central North Sea: tunnel valley fill sedimentary architecture
Published:January 01, 2012
M. Stewart, L. Lonergan, G. Hampson, 2012. "3D seismic analysis of buried tunnel valleys in the Central North Sea: tunnel valley fill sedimentary architecture", Glaciogenic Reservoirs and Hydrocarbon Systems, M. Huuse, J. Redfern, D. P. Le Heron, R. J. Dixon, A. Moscariello, J. Craig
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Fourteen overlapping 3D seismic reflection data sets, originally acquired by the oil and gas industry, were used to image and investigate complex networks of buried tunnel valleys in the UK sector of the Central North Sea. More than 180 individual tunnel valleys were observed and mapped to horizontal resolutions of 12–50 m and vertical resolutions of 8–10 m. The results presented here identify three recurring seismic facies that locally define stratigraphic organization from base to top of the buried tunnel valley fills: (i) high-amplitude disrupted units, (ii) a unit containing gently dipping disrupted reflections or transparent facies and (iii) well-layered continuous reflections. A comparison to similar works in the region is used to infer tunnel valley infill during changing depositional conditions from high-energy subglacial meltwater to quiet glaciolacustrine or glaciomarine environments.
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Glaciogenic Reservoirs and Hydrocarbon Systems
Glaciogenic reservoirs and hydrocarbon systems occur intermittently throughout the stratigraphic record, with particular prominence in Neoproterozoic, Late Ordovician, Permo-Carboniferous and Late Cenozoic strata. Recent interest in glaciogenic successions has been fuelled by hydrocarbon discoveries in ancient glaciogenic reservoirs in North Africa, the Middle East, Australia and South America. Glaciogenic deposits of Pleistocene age are noteworthy for their content of groundwater onshore and potentially prospective and/or hazardous gas accumulations offshore. The abundant imprints of Pleistocene glaciations in both hemispheres can be used to reconstruct complex histories of repeated ice cover and retreat, and glacier-bed interactions, thus informing our view on the dynamics of older ice caps and predictions of future glaciations. This volume aims to provide a better understanding of glaciogenic processes, their stratigraphic record and reservoir characteristics of glaciogenic deposits. The book comprises 3 overview papers and 16 original case studies of Neoproterozoic to Pleistocene successions on 6 continents and will be of interest to sedimentologists, glaciologists, geophysicists, hydrologists and petroleum geologists alike.