PARIS– Robertson Geolab, part of CGG’s GeoConsulting division, is performing a surface geochemistry (shallow core) survey to detect seafloor seepages of hydrocarbons in the southeastern Norwegian Barents Sea.
The survey, pre-funded by various oil companies, covers all blocks recently proposed for licensing by the Norwegian Petroleum Directorate.
The work involves sampling of outlying sub-areas where hydrocarbon seepages could be present using techniques such as satellite image analysis from NPA Satellite Mapping.
The coring method entails dropping a thin, iron core barrel which penetrates the seafloor sediments to a few meters depth to capture mud samples.
The main aim is to uncover active petroleum systems in the area and to identify prospective structures of all sizes. Geochemical analysis of the gaseous and liquid hydrocarbons in the sediments should help determine the gas- or oil-affinity of the petroleum systems and the sourcing/maturity of the hydrocarbons.
Oil companies can use the data to de-risk prior to conducting more detailed investigations. The survey is also important, CGG says, in limiting future environmental issues, i.e. over-drilling, and in assessing background levels of natural seafloor seepage pollution.
CGG says the data will be processed to provide a comprehensive geochemical interpretation report, including anomaly mapping in ArcGIS format, for assimilation into clients’ ownseismic or geological databases. The final should be available in December.