Geodynamic Evolution and Prospects of Oil-Gas Potential of Arctic Seas
V. S. Shein
All-Russia Research Geological Oil Institute, Moscow, Russia.
The main Arctic paleostructures are: 1. Paleo-continents - East-European, Siberian, North-American; 2. Paleo-mesocontinents - Arctic, Barents, West Siberian; 3. Paleooceans - Pre-Uralian, Uralian, Paleo-Asian, Pantalassa, Iapetus, South Anyui and 4. Arctic Ocean. Within these structure rifts, passive and transform continental paleomargins, island arcs, plate collision orogens and other plate-tectonic structures have been formed. During the five main geodynamic evolution stages the structures have been arising and transforming: the first stage - Precambrian (Riphean)-Early Cambrian, 2 - middle Cambrian - early Devonian, 3 - middle Devonian - Triassic, 4 - Jurassic - Early Cretaceous, 5 - Late Cretaceous - Cenozoic. Oil-gas-prone (OGPB) and potentially oil-gas-prone basins (POGPB) of different types were formed consequently: 1 - continental paleorifts and over-rift depression basins; 2 - oceanic rifts and deep-water depression basins; 3 - passive continental paleomargins basins; 4 - plate collision orogens, 5 - transform continental paleomargins and island arcs basins.
Oil-gas content of Arctic are established in 12 OGPB, 8 of which are located within Russia. Besides that 8 potentially oil-gas-prone basins were picked out in Russia. Oil and gas pools are discovered in Paleozoic, Mesozoic and Cenozoic deposits.
In Paleozoic complex they confine to Devonian, late Carboniferous - early Permian carbonates, late Permian terrigenous and carbonate reservoirs. Prospective reservoirs of the Western Arctic for oil and gas exploration are examined in the middle-late Carboniferous, Devonian deposits, sulfate-dolomite layer of visean-serpukhovian age and shaly-marly layer of kinovsko-sargaevskiy horizont might serve as seal for them.
Triassic terrigenous gas complex extend within of Barents Sea gas-oil-prone basin. Prospects of its gas-oil-contain is associated with the west and central parts of Barents Sea, where good quality reservoirs are proposed. Foreign basins fields in Triassic section are known within the limits of Sverdrup, Norwegian, Alaskan-Chukotkan oil-gas-prone basins.
Jurassic terrigenous complex contains unique gas reserves within the Barents Sea gas-oil-prone basin. Central part is the most perspective here, high-capacity reservoirs distribution, favorable conditions for gas generation and accumulation are forecasted there. Foreign countries pools are known within Sverdrup and Norwegian basins.
Large gas pools in the Cretaceous terrigenous complex are known within Kara subbasin of Western Siberia. It is supposed, that oil-gas-accumulation zones are associated with displacements in rifts of the northwest and northeast directions. Displacements appearance in the modern time might favor for good quality reservoirs formation in Kara Sea, Barents Sea, where large hydrocarbon pools are supposed. At foreign countries large oil and gas pools in terrigenous deposits of lower Cretaceous are detected within the limits of Sverdrup, Alaskan-Chukotkan oil-gas-prone basins. The comparison North-Alaska (USA) oil-gas-prone basin geological structure and East-Arctic (RF) permit to prognoses large hydrocarbon pools at the second one.
In decreasing order of oil-gas-contain's prospects it is possible to plan the following sequence according to it's tectonic types: 1 - continental rifts and over-rift depression basins (South-Kara subbasin, Barents OGPB, Laptev OGPB); 2 - passive continental paleomargins basins and marginal depressions associated with them (Timan-Pechora OGPB, Yenisei-Anabar GOPB, Eastern Arctic POGPB); 3 - transform continental paleomargins basins (Anadyr, Khatyrka GOPB, West Kamchatka GOPB, Penzhin, Olyutorsk-Komandorsky, Navarinsky, Aleutian POGPB); 4 - plate collision orogens (Novosibirsk-Chukchi, Verkhoyansk, Zyryansky POGPB); 5 - noantransfom passive continental margins (Spitsbergen, Franz-Josef Land, Kara, Severnaya Zemlya, Novosibirsk and others); 6 - island arcs basins (West Mendeleev, Toll’, Makarov); 7 - oceanic rifts (Nansen, Amundsen POGPB).
Exploration priority directions in Arctic are Cretaceous and Jurassic deposits of South-Kara subbasin, Jurassic and Triassic deposits of Barents sea central part and Paleozoic deposits within its boundaries zones, and also oil and gas pools exploration in Paleozoic deposits of Timan-Pechora OGPB offshore. At the eastern Arctic the main tasks are regional research and preparation of oil and gas exploration objects in deposits from Carboniferous to Paleogene.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia