The Atzbach-Schwanenstadt Gas Field - A Potential Site for Onshore CO2-Storage

Within the framework of the EU-funded CASTOR project the Atzbach-Schwanenstadt gas field in Upper Austria is being investigated as a potential underground CO2 storage site. Potential CO2 sources are a paper mill and a fertiliser plant. <br>The digital geological model ranges from the base of the Hall Series (Miocene) to the Top Eocene, with a special focus on the main reservoir zone ("A4") of the Upper Puchkirchen Series (Oligocene to Miocene). Reservoir properties were stochastically assigned, conditioned by their occurrence in the wells with petrophysical interpretation and by their statistical distribution in the various facies.<br>The reservoir model focuses on the A4 zone and includes only the central part of the field, where gas productivity is best and where a relatively uniform gas-water contact exists. Reservoir parameters were upscaled from the geological model to yield a model size that enables fast simulations. It is expected that injected CO2 will during the potential injection period replace produced gas in the reservoir. So far, approx. 3.2×109 sm3 gas have been produced from the field. Assuming that CO2 can replace all produced gas, this corresponds to a storage capacity of at least 3 million tonnes of CO2.