A large portion of the Arctic is represented by the Eurasian Shelf - the largest area of continental shelf on Earth. The Laptev, East Siberian and Chukchi seas in the Siberian Arctic occupy almost half of the shelf area. The area is remote from present-day markets and represents one of the most extreme hydrocarbon (HC) frontiers worldwide. Our recent studies show there are as many as 20 large sedimentary basins of variable age and genesis in the Siberian Arctic Continental Margin (SACM). They are thought to bear a significant volume of undiscovered HC resources which is still difficult to estimate due to limited geological and geophysical data and absence of drilled wells. However, based on a comprehensive regional compilation of all available geodata, we can outline the main structural features, possible HC systems and play elements.
The various sedimentary basins resulted from creation and subsequent disintegration of the Proterozoic and Phanerozoic supercontinents. The most important tectonic events controlling the structure and petroleum geology of the entire Eurasian Arctic shelf are:
1. Late Paleozoic Baltica and Siberia collision;
2. Jurassic rifting and subsequent Early Cretaceous opening of the Canada oceanic basin and counterclockwise rotation of the North Alaska-Chukchi Microplate;
3. Early Cretaceous closure of the Anyui Ocean due to convergence of the North Alaska-Chukchi Microplate and Siberian margin and their subsequent collision along the South Anyui Suture;
4. Greenland/Ellesmere and Greenland/Barents convergence between 56 and 33 Ma and related crustal re-adjustment in the Barents-Kara region;
5. Opening of the Eurasia oceanic basin (53-0 Ma) and related rifting and crustal re-adjustment in the SACM;
6. Indostan/Eurasia collision (40-10 Ma) which triggered large scale crustal re-adjustment over the entire Asia and North East Asia.
The majority of SACM sedimentary basins were formed as rift and post-rift basins, and later modified through a series of inversions. Favorable source rock depositional conditions may have occurred in the Vendian, Cambrian, Late Devonian, Permian, Triassic, Jurassic, Cretaceous and Early Tertiary. However the pre-Mesozoic and early Mesozoic systems are thought to be poorly preserved over SACM due to a series of orogenic events. The Late Cretaceous and Tertiary were times of deltaic and shallow marine deposition over broad areas of the SACM enhancing the chance for reservoir development. Trap development is mainly related to N. Atlantic-Arctic plate readjustments. Trapping style includes extensional and inverted rotated fault blocks, rollover anticlines, wrench related anticlines and stratigraphic traps.