Geophysical modelling comparison at varying saturation and pressure: CO2 sequestration pilot project at Otway Basin

Abstract

The Otway Basin CO2 sequestration pilot project aims to demonstrate that CO2 can be safely stored in a depleted gas field and that an appropriate monitoring strategy can be deployed to verify its containment. The advantage of injecting CO2 into a depleted gas field is having access to well-established infrastructure, pre-existing geophysical exploration data, and production wells. On the downside, the geological complexity of the Naylor gas field, which is relatively deep and of a small size (0.5km2), presents challenges for detailed geophysical and geological characterization and consequently makes the design of a geophysical monitoring program much more difficult. Uncertainty of the location of paleo and current gas-water-contact poses additional difficulty for positioning of the injection well. These factors call for further analysis of all available geophysical data.