Classification and Comparison of Fluid flow Systems in the SW Barents Sea

The SW Barents Sea is a large hydrocarbon-prone basin of the Norwegian Arctic region. A significant portion of the hydrocarbon gases has leaked or migrated into the shallow subsurface and is now trapped in gas-hydrate and shallow-gas reservoirs. Leakage of gas into the shallow sediments and into the ocean through the seafloor was probably the result of the profound Cenozoic erosion of the Barents Sea shelf during various glaciations. The flow of these fluids through marine sediments may have controlled the evolution of the various sedimentary basins of this region. We analyzed 2D seismic data from different basins of the SW Barents Sea to identify different fluid-flow features, classify them and study their relation to structural elements and geological history of SW Barents Sea. Most of the identified features fall in the category of gas chimneys, fault leaks and high-amplitude anomalies. Several complex fluid-flow features, a combination of chimneys and faults, were quite common suggesting a relation between the timing of faults and fluid leakage. The gas chimneys are observed to be originating from the Jurassic and older formations as evident from some seismic lines. The chimneys terminate at shallow stratigraphic levels leaving high-amplitude reflections or connect to the pockmarks at the seabed. Some chimney features terminate at small faults which act as further pathways for fluid migration. Submerged pockmarks or depression-like features are also observed at shallow stratigraphic levels of some lines. The chimneys show good relation to the structural setting of the SW Barents Sea. Most of the chimney features coincide with major faults in the SW Barents Sea suggesting a relation between fluid flow and deep seated faults and confirms the Pre Jurassic roots of the gas chimneys. The leakage through faults is also evident in the seismic data. High- amplitude anomalies are observed at the terminating points of chimneys and faults suggesting occurrences of shallow gas.