Abstract
The formation and evolution of the East Barents Sea basin were related to the closure of Ural Ocean, which resulted in three different prototype basins. Based on dynamic research on basin-forming & hydrocarbon generation & hydrocarbon accumulation, filling mechanisms of the East Barents Sea Basin in different superimposed-phases are proposed. By adopting the approach of multi-factor joint control, hydrocarbon accumulation and distribution laws of the basin are raised. The East Barents Sea Basin was characterized by multiple reservoir-cap combinations, multi-phase generation and expulsion of hydrocarbon and multi-cycle hydrocarbon accumulation in the basin . Its stratigraphic sequences can be divided into three sets by two major geological events I1 (P2) and B (T-J, K1), the lower carbonate sedimentary sequence (LCSS) was related to the closure of the Ural Ocean in the passive continental margin, as well the middle rift sedimentary sequence (MRSS) to the Ural movement and the upper depression sedimentary sequence (UDSS) to the Novaya Zemlya movement . Multifunctional elements influenced hydrocarbon reservoirs both in formation and distribution in the superimposed basin. Post basin's forming did great damage to the earlier basin's. The rapid stretch and subsidence (maximum speed of 150 mm/a) of the basin controlled the high maturity of source rocks during Late Permian – Triassic rift period . Thus during depression period reservoir-cap assemblages revealed two sets of favorable plays. The two structural inversions in Mesozoic and Cenozoic impacted dramatically on the main types and distribution of the hydrocarbon traps. In this case the match of hydrocarbon from different source rocks and different generation phases with traps brought about the hydrocarbon reformation models with strong and weak superimpositions. So five hydrocarbon accumulation models are presented . The favorable exploration areas are in the large scale conversion anticlines, Tertiary strike-slip faults, the slope deltas on basin edge, the inherited protrusions in the depression center related to the Late Triassic inversion, the uplifts inside the basin, the horsts and the grabens, and also the reefs in the LCSS .
