|
1 Newcastle Research Group in Fossil Fuels & Environmental Geochemistry (NRG), Drummond Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK
2 Saga Petroleum a.s., Kjørboveien 16, Postboks 490, 1301 Sandvika, Norway
Whereas the processes of petroleum generation and primary migration are beginning to be understood from a quantitative viewpoint, the process of secondary migration is still incompletely quantitatively understood. We estimate that typically the carrier systems feeding Brent Group reservoirs contain an average of around 3% residual oil saturation, the petroleum flowing in high saturation petroleum rivers through the most permeable carrier bed zones. Most of the carrier porosity contains no petroleum. The filling of the Brent Group reservoir in the Gullfaks field (Tampen Spur) is elucidated by petroleum geochemistry and this study indicates that the field has filled from more than one source basin and has been biodegraded post oil-emplacement. The complex filling and degradation history suggests that geochemical study of reservoir petroleum columns is a useful exercise providing information on the fillpoints of these complex reservoir systems and potentially information on the palacohydrogeology of the area.
