Research paperStructural and stratigraphic controls on subsurface fluid flow at the Veslemøy High, SW Barents Sea

- Fluid flow governed by structural geometry, faults and silica diagenesis zones.
- Opal CT zones are acting as fluid accumulation zones.
- Opal A-Opal CT boundary is guiding fluid flow towards structural highs.
- Presence of characteristic assemblages of seep related benthic foraminifera.
- Abundance of condensate-type, light hydrocarbons.

Subsurface and seafloor fluid flow anomalies are gaining large interest after the finding of five new hydrocarbon discoveries and observation of large gas flares in the SW Barents Sea. In the present study, we have analysed structural and stratigraphic controls on fluid flow towards the seafloor using gravity cores selected based on subsurface gas anomalies observed on seismic data from the Veslemøy High, SW Barents Sea. The subsurface fluid flow at the Veslemøy High is observed to be controlled by 1) the morphology and orientation of regional faults, structural highs and sedimentary basins, 2) the presence of Paleocene silica ooze deposits that changes microstructure with temperature thereby controlling fluid flow and 3) the location of regional and local open faults formed by glacial loading and unloading. Analysis of extractable organic matter in subsurface Holocene sediments corroborates the active migration pathways inferred from seismic data. Micropalaeontological studies on benthic foraminifera reveal methane seep associated assemblages that confirm the interpretation of subsurface gas anomalies in seismic data. We ultimately link these new results to the geological evolution history of the region to give a comprehensive model for the fluid flow system within the study area.