Global greenhouse gas emissions, due to human activities, have increased since the start of the industrial revolution in the mid-19th century, with a 70% increase over the last 40 years. (IPCC 2005). The growth in emissions is linked to the growing demand for energy services which will keep the use of fossil fuels high for the foreseeable future (IEA 2004). A promising and increasingly studied method for reducing greenhouse gas emissions and mitigating climate change is to capture CO2 from large stationary sources, such as coal-fired power plants and refineries, and inject under supercritical conditions into deep underground geological formations. Formations considered potential hosts include depleted oil and gas reservoirs, salt domes, unexploitable coal deposits, and deep saline aquifers (White et al. 2012). These are believed to offer the greatest potential for CO2 storage due to their large storage capacity and wide availability (Bachu 2003; Michael et al. 2010). The key issue for successful long-term storage in saline aquifers is the hydraulic integrity of saline aquifers. geological formations which delimit it. (Eiken et al. 2011). A seal liner is the essential geologic structure that prevents the upward migration of buoyancy-induced CO2. However, geological imperfections within the host formation and/or in the cap rock can result in leakage of CO2 into overlying permeable formations. Therefore, leak risk assessment has become one of the main challenges in CO2 capture and storage operations. Faults and fault rocks are the main natural imperfections and are predominant in many sedimentary basins suitable for CO2 storage. In general, faults and fault rocks can act as baffles or potential barriers.... middle of paper .... .. Childs, C. & Walsh, JJ 2010. Faults and properties of faults in models hydrocarbon flow. Geofluids, 10, 94-113.Michael, K., Golab, A., Shukalova, V., Ennis-King, J., Allinson, G., Sharma, S. & Aiken, T. 2010. Geological storage of CO2 in saline aquifers. A review of the experience of existing storage operations. International Journal of Greenhouse Gas Control, 4, 659 - 667. Tueckmantel, C., Fisher, QJ, Manzocchi, T., Skachkov, S. & Grattoni, CA 2012. Two-phase fluid flow properties on cataclastic faulted rocks : implications for CO2 storage in saline aquifers. Geology, 1, 39-42.White. CM, Strasizar, BR, Granite, EJ, Hoffman, JS & Pennline, HW 2003. Separation and capture of CO2 from large stationary sources and sequestration in geological formations - coalfields and deep saline aquifers. Journal of the Air and Waste Management Association, 6, 645 - 715.