PETROMAKS-Maksimal utnyttelse av petroleumsreserver

Re-Os (rhenium-osmium) isotope geochemistry is emerging as a powerful tool for geochronology and tracer studies in petroleum systems. Both Re and Os are concentrated in organic material fixed in marine shales by reduction from seawater. The decay of 187 Re to 187Os provides a radiometric clock for determining the age of deposition of carbonaceous shales, placing absolute time pins in the sedimentary record. Homogenization of hydrocarbons during migration resets the clock, so that Re-Os geochronology of migrated hydrocarbons constrains timing of migration. The 187Os/188Os ratio of the shale at the time of hydrocarbon generation is a fingerprint linking the shale and migrated components. These concepts have proven true for individual cases. To fully de velop Re-Os applications for petroleum exploration, the next step is basin-scale assessment and integration with biostratigraphy and other geochemical tracers. Extended or multiple periods of hydrocarbon generation, incomplete homogenization during migra tion, or mixing of hydrocarbons from multiple sources may introduce scatter. Large variability in 187Os/188Os, however, assures high resolution. By combining Re-Os constraints with operative models based on other data, complex petroleum systems can be m odeled effectively. We will apply this new approach to source rocks and oils from Norway's Arctic regions. A leading Re-Os laboratory from the USA (AIRIE Program) will provide technology otherwise not available in Norway. Two Norway-based companies, S tatoil ASA and Eni-Norge AS, will provide oil samples and collaborate on interpretive models, benefiting from early access to new data and concepts. SINTEF will share expertise on biostratigraphy and geochemistry for the selected study sections. Two pos tdoctoral fellows, recruited for their interest in the Norwegian industry, will master Re-Os analytical methods and help integrate isotopic data with models for basin evolution and hydrocarbon migration.