--> Abstract: Seismic - Geological Preconditions of Oil Presence in Paleozoic and Mesozoic Deposits of the East Barents Sea, by B. V. Senin and M. I. Leontchik; #90096 (2009)

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Seismic - Geological Preconditions of Oil Presence in Paleozoic and Mesozoic Deposits of the East Barents Sea

Boris V. Senin and Mikhail I. Leontchik
JVC Soyuzmorgeo, Gelendzhik, Russia.

The main tectonic peculiarity of basins in the eastern part of the Barents Sea is their location within the East Barents Trough where areas of “graniteless” crust are developed and total thickness of sediments is about 20 - 24 km. Some structural-geological and sedimentation features of these basins resemble ones of the Pricaspian and South Caspian megabasins.

Prospects for oil presence are mainly connected with the offshore portion of the Timan-Pechora Province according to modern ideas, whereas the East Barents Sea rates as gas-bearing mainly. At the same time, numerous oil-shows in wells and insular outcrops of Paleozoic and Triassic rocks on the periphery of the East Barents Trough within both Russian and Norwegian sectors and oil pools in Triassic deposits indicate high outlook for oil presence in the open portion of the water body.

Facts of catagenetic «inversion» i.e. decrease of organic matter maturity with depth in some sections of the Barents Sea, extended catagenesis scale in deep depressions with a thick sedimentary cover (20-25 km) and submergence of the oil window lower boundary down to 6-8 km sometimes as well as statistically grounded ideas about possible generation of liquid hydrocarbons at temperatures up to 200oC support the supposition that conditions in the modern East Barents Trough may be favorable for oil generation and accumulation. In this connection, the Middle Paleozoic - Middle Mesozoic portion of the section at least may be oil-promising.

Main hopes of oil presence in the region are pinned on two regional mega-formations in the sedimentary cover of the trough - the Paleozoic terrigenous-carbonate and the Permian-Mesozoic terrigenous ones.

Reinterpretation of retrospective seismic lines and new surveys revealed a wide range of potential HC traps of sedimentary origin in these formations.

Upper Devonian - Lower Permian terrigenous - carbonate deposits of the Kola and Murmansk Monoclines, the Korginsky and Kurentsovsky Steps, and the Prednovozemelsky Foreland comprise isolated reef bodies and lines of those confined to steps in transition zones between the inner and outer shelf and to terraces of the ancient continental shelf.

Upper Permian terrigenous deposits within the South Prinovozemelsky Zone, the Kurentsovsky Step, and the Kola Monocline contain sandy bodies related to fans and deltaic formations that may be of interest for HC prospecting though seals, missing or incompletely developed in connection with lock of sedimentation, erosion, or tectonic destruction of corresponding deposits may be a problem in the monocline.

Triassic deposits comprise land and underwater complexes of valleys and river mouths that form thick delta and avant-delta bodies accumulated in quickly alternating environments of underwater channels, coastal shallow water zones, and occasionally flooded lowland. One of such objects (a large paleovalley) is revealed in Middle and Upper Triassic deposits of the Kola and Murmansk Monoclines.


AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia