Imaging fluid migration-path networks for understanding the geo-constraints associated with fluid flow and venting mechanisms in gas-hydrated sediments of SW Barents Sea

Recent finding indicates that the rapid degassing of the Arctic shelves and slopes may have already begun and that methane is indeed being released in to the atmosphere. We therefore have to make sure that we fully understand the complex, interlinked geophysical, geological, geochemical and microbiological systems operating in the sediment and water column to develop models that allow predicting the circumstances in which significant amount of methane will reach the atmosphere in the near future. High resolution P-Cable 3D seismic data were acquired from selected key areas in the Barents Sea in ~ 200 - 350 m water depths. In this region the gas hydrates are widespread and often occur in conjunction with deep gas-reservoir leakage, in which potential sources of methane or anomalous seafloor methane fluxes have already been identified. The overall objective of the study is to determine geo-fluid pathways and sites of gas hydrate formations. Gas hydrates and shallow gas reservoirs are sites that are potentially important for our understanding of natural methane storage and release systems, particularly on Arctic continental margins, where environmental changes are believed to be more severe than elsewhere. In recent years, shallow gas accumulations on the Norwegian Margin and the Barents Sea are potentially seen as new play type reservoirs beneath highly compacted glacial sediments. The shallow gas reservoirs are little understood in terms of sediment architecture, seal integrity and leakage conditions and they are also important in terms of providing windows to deep hydrocarbon reservoirs. Their location in the Barents Sea might also be linked to reservoirs in the less explored Triassic and Palaeozoic successions. Many fluids and gas anomalies exist in the SW Barents Sea, particularly at the border between the Polheim sub-platform, Loppa High and Hammerfest basin. Other places with gas anomalies are known to concentrate between the Polheim sub-platform and Veslemøy high. We wish to determine and understand better: (1) the distribution of shallow gas and migration pathways; (2) the distributions and concentrations of gas hydrates and (3) the geo-constraints governing fluid flow characteristics from deep sources to sites of shallow accumulation.