Chapter 21 The geological evolution and hydrocarbon potential of the Barents and Kara shelves

Abstract

AbstractAll of the Arctic Eurasian Basins – the Barents and Kara Seas and the adjacent parts of the Pechora and West Siberian basins – have intracratonic settings and were affected by phases of intracratonic rifting during Riphean, Early Palaeozoic, Devonian–Early Carboniferous, Early Triassic, Jurassic and Cenozoic times. Often these stages were simultaneous at remote areas. The rifting led to the development of extensional sag basins giving thick sedimentary complexes associated with linear rifts and creating trends favourable for hydrocarbon generation. These trends are defined by the major fault complexes bordering them and include linear positive inverted structures and thick sedimentary complexes. The tectonic processes within these trends influenced the later structuring of the whole basin and the distribution of hydrocarbons. Hydrocarbon generation started long before the present basins’ structural configuration formed, and oil and gas kitchens were associated mainly with extensional parts of the basins. Later phases of rifting and extension affected both the ancient oil and gas kitchens and the younger ones. Inversion caused trapping and affected fluid migration, mixing the petroleum systems. Inverted structures in the old rifts have the highest potential for large hydrocarbons accumulations but, in highly uplifted areas affected by faulting and erosion, exploration risk is high.