Abstract

The Eastern Barents, Kara, Laptev, East Siberian seas and the western Chukchi Sea occupy a large part of the Eurasian shelf in the Russian Arctic. This huge region consists over 40 sedimentary basins of variable age and genesis, which are thought to bear significant undiscovered hydrocarbon resources. Apart of the East Barents and South Kara shelves with proven world-class gas and gas condensate resources, the rest of the basins are undrilled and explored with rather sparse grid of regional 2D seismic lines.

The majority of the sedimentary basins were formed and developed in a rift and post-rift setting and later modified through a series of structural inversions. Important tectonic events controlling the structure and petroleum geology of the basins are: the Caledonian collision and orogeny followed by Late Devonian to Early Carboniferous rifting, Late Paleozoic Baltica/Siberia collision and Uralian orogeny, Triassic and Early Jurassic rifting, Late Jurassic to Early Cretaceous Canada Basin opening accompanied by closure of the Anyui Ocean, the Late Mesozoic Verkhoyansk-Brookian orogeny, and Cenozoic opening of the Eurasia Oceanic Basin.

Using available regional seismic lines correlated with borehole data, onshore geology in areas with no exploration drilling, and the Arctic-wide magnetic, bathymetry and gravity grids, we provide more confident characterization of the regional structural elements of the Russian Arctic shelf, and constrain the timing of basin formation, structural styles, lithostratigraphy and possible petroleum systems and plays in frontier areas.

Introduction

A significant part of the Arctic is represented by the Eurasian shelf which is the largest shelf on Earth. Its major portion (about 3.5 million km2) is located in the Russian Arctic and is occupied by the eastern part of the Barents, Kara, Laptev, East Siberian and a western part of the Chukchi seas (Fig. 1). A systematic geological study and airborne gravity and magnetic measure-ments of the vast Russian Arctic shelves (RAS) commenced soon after the World War II. The main exploration effort over the entire RAS was undertaken during the latest period of the Soviet era when extensive coverage of regional refraction and 2D reflection seismic lines was acquired over the eastern Barents and southern Kara seas by Marine Geological Expedition (PMGRE, St. Petersburg), Marine Arctic Geological Expedition (MAGE, Murmansk), SevMorGeologiya (SMG, St. Peters-burg) and SevMorNefteGeofizika (SMNG, Murmansk). Some of the large prospects were successfully tested during the 1980s and several large discoveries were made including the gigantic Shtokman, Rusanovskoe and Leningradskoe gas and gas con-densate fields.

The Siberian shelves, which are the most remote from the present-day markets, remain poorly explored. They represent one of the most promising petroleum frontiers worldwide. They are explored by an irregular grid of wide-angle refraction and 2D regional multichannel seismic reflection (MCS) lines acquired mostly between 1975 and 1997 by PMGRE, MAGE, Laborato-ry of Regional Geodynamics (LARGE, Moscow) and SMNG in cooperation with German Federal Institute for Geosciences and Natural Resources (BGR, Hannover) in the Laptev Sea; LARGE and DalMorNefteGeofizika (DMNG, Sakhalin) in coop-eration with Halliburton Geophysical Services - in the East Siberian and Chukchi seas. A recent seismic survey by the TGS-Nopec Geophysical Company AS provided modern high quality data acquired with a 6 km long streamer in the Russian Chukchi Sea (Verzhbitsky et al. 2008).

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