Publication Name: PESA's Eastern Australasian Basin Symposium II
Authors: J. Sayers, A. Kernich and T. Dance
Date Published: December 2004
Number of Pages: 31
Reference Type: Book Section
Abstract:
Greenhouse gas emissions from large stationary emission point sources in the Sydney region represent 15% of the total Australian emissions. In contrast, the potential for onshore geological CO, storage sites to accommodate this source is relatively modest. This imbalance highlights the need to assess the CO, geological storage potential offshore.The offshore sedimentary basins of New South Wales are predominantly devoid of modern seismic data and no
petroleum exploration wells have been drilled. Unstacked regional seismic data of 1971 vintage were used to assess the top and base of the Cainozoic sediment wedge, despite its poor quality. Normal moveout correction of the two horizons interpreted allowed a more accurate estimate of the two-way-time. Preliminary depth and isopach maps were constructed to ascertain the geometry of the Cainozoic sediment wedge and potential pre-Cainozoic structures.
Refractor velocities range from 4.0-6.2 km/s indicating the presence of high-velocity rocks under the Cainozoic
sediment wedge. This suggests the continuation offshore of the New England and Lachlan Fold Belts north and south of the Sydney Basin, implying little geological storage potential in these areas.
The study identified 15 potential geological CO, storage sites, although a lack of drilling data meant that a full
assessment of the sites could not be made. A preliminary review of the key risk factors revealed that storage capacity estimates are in the order of several TCF, reservoir injectivity may be difficult due to poor reservoir quality and a pre-Cainozoic seal is required to seal CO, in a supercritical state.