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Houston, TX, United States

Fontana P.,Polarcus | Makhorin M.,Polarcus | Cheriyan T.,GX Technology | Saxton L.,GX Technology
SEG Technical Program Expanded Abstracts | Year: 2011

A 2D towed streamer acquisition experiment was conducted in deep water offshore Gabon to evaluate techniques to optimize seismic reflection data within narrow low frequency bands through the use of a low frequency source, deep towed solid streamers, and long offsets. These techniques proved effective and should be applicable in many areas where the primary exploration targets are deep in the rock section and/or are overlain by high impedance low-pass salt, basalt, or carbonate structures. © 2011 Society of Exploration Geophysicists. Source

Kumar N.,GX Technology | Danforth A.,GX Technology | Nuttall P.,GX Technology | Helwig J.,GX Technology | And 2 more authors.
Geological Society Special Publication | Year: 2013

The first comprehensive geological and geophysical surveys of the Brazilian continental margin during the 1970s recognized the crust in the SE Brazilian basins as 'anomalous' but models for the opening of the South Atlantic proposed at that time invoked a very narrow continent- ocean transition. Nevertheless, such studies established the presence of a thick sedimentary prism, including an extensive salt layer under the São Paulo Plateau. The earliest reconstructions for the South Atlantic invoked a seaward shift of the spreading axis to account for the asymmetric widths of the salt layer between the Brazilian margin and its conjugate in offshore Africa. Although our understanding of continent-ocean transition has progressed since then, direct seismic imaging at crustal scale has only been possible recently through long offset (10 km), deep recording (18 s), pre-stack depth migrated (PSDM) to 40 km, seismic-reflection data. These data allow us to generally image the Moho from under thick continental crust (> 30 km) to thin oceanic crust (c. 5 km). Although the nature of the transitional crust is still contested, these seismic data allow for constraints on various models for continent-ocean transition. Future integrated studies utilizing PSDM and refraction-seismic data will further refine these models. © The Geological Society of London 2013. Source

Mohriak W.U.,State University of Rio de Janeiro | Danforth A.,GX Technology | Post P.J.,Ocean energy | Brown D.E.,center | And 4 more authors.
Geological Society Special Publication | Year: 2013

The main objective of this book is to provide a global overview of divergent margins based on geological and geophysical interpretation of sedimentary basins along the South, Central and North Atlantic conjugate margins, from plate tectonics and crustal scales to a more detailed description of stratigraphical and structural elements that are responsible for petroleum plays. These themes are complemented by geodynamic concepts based on physical and numerical models, and by comparisons with present-day embryonic margins, which are succinctly discussed in some papers. © The Geological Society of London 2013. Source

Helwig J.,GX Technology | Kumar N.,GX Technology | Emmet P.,GX Technology | Dinkelman M.G.,GX Technology
Geological Society Memoir | Year: 2011

Three new regional 2D seismic surveys in the Beaufort Sea provide a broad, deeper view of basins and crustal structure of the Meso-Cenozoic Canadian Arctic passive margin. The seismic profiles cover 16 270 km from inner shelf to over 2000 m water depth and include areas previously unsurveyed due to sea-ice limits. The surveys cover offshore Mackenzie Delta and extend north to Latitude 74°N off Banks Island. Geological interpretation is tied to exploratory wells in the Beaufort-Mackenzie Basin that has yielded 48 oil and gas discoveries in Cretaceous-Oligocene sandstones. The entire Meso-Cenozoic passive margin wedge beyond the depocentre ties into this established petroleum system. Three segments of the margin are defined by orientation and structural styles, from typical passive margin geometry to wrench structures to a compressional foldbelt superposed on the western segment. Outboard seismic profiles image oceanic crust and the inferred extinct spreading centre of the Canada Basin. The continent-ocean boundary is interpreted using gravity data supported by deep seismic reflectors. The regional deep imaging of the tectonic architecture, structural sequence and tectonostratigraphy of each segment are major results, and advance the understanding of the geological framework of known and potential petroleum basins of the Arctic margin of Canada. © 2011 The Geological Society of London. Source

Kumar N.,GX Technology | Granath J.W.,GX Technology | Emmet P.A.,GX Technology | Helwig J.A.,GX Technology | Dinkelman M.G.,GX Technology
Geological Society Memoir | Year: 2011

The US Chukchi Shelf is a proven petroleum province similar to the prolific hydrocarbon-bearing region in the adjacent North Slope of Alaska. This shelf is part of the Arctic Alaska plate that was presumably connected to the Canadian Arctic Islands until the opening of the Canada Basin. A new data set (3130 km) of deep 2D seismic reflection profiles, acquired in 2006 and depth processed to 40 km, provides excellent images of the drillable (c. 8 km depth) stratigraphy as well as of deeper structures. The data also permit regional mapping of the tops of crystalline basement and the Moho discontinuity. The area has a tectonic history of multiple phases of rifting: a pre-Late Devonian phase that culminated in inversion and thrusting; a Late Devonian-Mississippian phase that accommodated Ellesmerian sedimentary deposits as a sag sequence; and a Jurassic to Early Cretaceous phase that is contemporaneous with the opening of the Canada Basin. Hanna Trough is recognized as a Palaeozoic basin with a multistage history while the North Chukchi Basin formed in early Cretaceous as an extensional basin. Only five wells have been drilled in the area; hence numerous opportunities for further exploration exist in the Chukchi Shelf. © 2011 The Geological Society of London. Source

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