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Influence of Host Rock Lithology Contrast on Permeability Reduction in Fault Zones (Vienna Basin, Austria)
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Fifth International Conference on Fault and Top Seals, Sep 2019, Volume 2019, p.1 - 5
Abstract
In order to calibrate fault seal capacities to a specific basin, faults were analysed using core material. This calibration was conducted on several Neogene hydrocarbon fields in the Vienna Basin, Austria. Laboratory results showed a significant permeability reduction in all fault rocks compared to the host rocks. The highest and lowest sealing capacities were observed in rocks classifying as cataclastic bands. Although these cataclastic bands showed a broad variation in sealing capacity, the reason for the strong variation could neither be related to the depth at time of faulting or secondary cementation nor the shale/phyllosilicate content or the maximum burial depth of the host rock. Therefore all samples underwent further microscopic investigation. The examined samples revealed that the sealing potential of the fault rocks is strongly linked to the detrital carbonate content in the host rock. Our study shows that addressing the lithology variations in the host rock should not be neglected for fault seal analysis.