Fault Characterisation from an Ultra-high-resolution Seismic for CO2 Injection Experiment

An ultra-high-resolution mini 3D survey was acquired at the Otway site to characterise structures and discontinuities in a depth range of 0-100 m for the controlled CO2 fault plane release experiment. The survey demonstrated that very high spatial data density is essential for imaging and characterisation of shallow structures. Nevertheless, significant processing efforts were required to precisely image shallow fault geometry and the extent of fault tips. The main fault F1 and the accompanied discontinuities were clearly imaged with a PSDM routine after a 3D velocity model was derived from 3D tomography and then further improved through an iterative process. Fault F1 now appears more complex and additional studies are needed. Further assessment of the fault F1 and its associated discontinuities will be conducted using three component seismic data.