A New Biostratigraphical Tool for Reservoir Characterisation and Well Correlation in Permo-carboniferous Sandstones

Permo-Carboniferous sandstones are important reservoir rocks for natural gas in the Southern North Sea basin. This is a mature area which makes tools for reservoir characterization and well to well correlation important for field optimalisation and ongoing exploration activities. Within the Permo-Carboniferous sandstone reservoirs of the Dutch on- and offshore there are two key questions which still need to be resolved. One regards the geological model for the basin infill, another is the detection of the Base Permian Unconformity (BPU), an important regional unconformity. Biostratigraphy is classically used to address these problems. As the traditional microfossil groups are absent in the Permo-Carboniferous redbed deposits, the application of biostratigraphy is seriously hampered. In this study, we present a new biostratigraphical tool based on biogenic silica microfossils (BSPs). This fossil group consists of siliceous plant remains which are preserved even under extreme oxidizing conditions. BSPs are present in the Permo-Carboniferous redbed sequences and are now for the first time used for biostratigraphical correlations. This new tool holds great potential for independent chronostratigraphical correlations in economically important redbed deposits worldwide. In this study the initial results from a case study in the Southern North Sea basin will be presented.