Carbon Capture and Storage (CCS)
Carbon capture and storage represents one method for helping to mitigate the effects of increasing CO2 concentrations on global climate. Whether the focus is on storage of CO2 that originates from anthropogenic sources or as a by-product of natural-gas production, monitoring is an essential part of CCS operations. Furthermore, in situations in which CO2 is used for enhanced oil recovery, monitoring can help control the injection process to maximise both oil recovery and CO2 storage. Regulatory agencies often require the application of 4D seismic and other geophysical methods to monitoring CCS projects. Monitoring serves several purposes. It provides information on safety and the environment, determining if injected CO2 is leaking through the caprock and potentially contaminating near-surface aquifers or reaching the surface. A more challenging application of geophysical monitoring is to provide the data required to verify the inventory of CO2 stored in the subsurface — information that is essential for the accounting of greenhouse-gas emissions and carbon-credit trading.
CRGC, through its research at the CO2CRC Otway test site in Victoria, and through its collaboration with institutions such as Lawrence Berkley National Laboratory, is playing a leading role in the application of geophysical monitoring to CCS. Current research is focused on monitoring of CO2 sequestration using 4D seismic data and time-lapse 3D VSP over Naylor field, Otway Basin, Victoria and Southwest Hub, Western Australia. Specific project areas include:
- analysis of seismic repeatability using field tests
- developing time-lapse processing flows and specialised algorithms for onshore 4D seismic data
- time-lapse seismic prediction using integration of geological modelling, flow simulations, rock physics, seismic forward modelling, and seismic noise estimation
- data acquisition using novel technologies, including buried geophones, permanent sources, and distributed acoustic sensors