Fault Stability and Potential Fault Reactivation Analysis in Otway Basin, Australia

Abstract

The CO2CRC (Cooperative Research Centre for Greenhouse Gas Technologies) started a pilot project for carbon dioxide storage, the CO2CRC Otway Project, in Nirranda South, Victoria, Australia in 2005. Several analyses have been conducted to demonstrate that carbon capture and storage (CCS) is technically and environmentally safe. In particular, our workflow uses a one-way coupled geomechanical model to assess fault stability and potential fault reactivation in order to prevent leakage of CO2 along faults. State of stress on the faults is checked against Mohr-Coulomb failure criterion in both cases. Fault stability analysis has been performed taking into account assumptions derived from regional studies. Critical pore pressures needed for fault reactivation have been calculated for injection scenarios using both analytical and numerical approaches.