<div>Ideally when combining different 3D seismic surveys differences in acquisition parameters warrant full pre-stack reprocessing from field data. However, there are occasions where this is not possible due to time, financial or data access constraints; a valuable alternative is post-stack merging and enhancement of existing migrations. The offshore Otway Basin was the subject of such a project, the objective of which was to produce a regularised and seamless 3D dataset of the highest possible quality, within a two-month turnaround time. The input migrated volumes varied by data extent, migration methodology, angle range and grid orientation. 14 input volumes totalling 8,092 km2 were post-stack merged and processed to produce a continuous and consistent volume, enabling more efficient and effective interpretation of the region. The surveys were regularised onto a common grid, optimised for structural trend, prior to survey matching. DUG’s mis-tie analysis algorithm, applied over a time window optimised for interpretation of key</div><div>events, was used to derive corrections for timing, phase and amplitude, using the Investigator North survey as a reference. This was followed by time-variant spectral and amplitude matching, with gain corrections applied, to improve continuity between volumes. Additional enhancements including noise removal and lateral amplitude scaling were also applied. The final merged volume offers significant uplift over the inputs providing better imaging of structure and event and dramatically improving the efficiency and quality of interpretation. This enables rapid reconnaissance of the area by explorers. Presented at the Australian Energy Producers (AEP) Conference & Exhibition

Geoscience Australia houses one of the world's largest collections of petroleum data. Much of this data is non-confidential and available to the petroleum industry, research organisations and the public. The collection includes seismic survey data submitted by industry under legislative requirements as well as data collected by research projects and marine surveys undertaken by Geoscience Australia or other government agencies or institutions. The collection comprises digital 2D and 3D seismic survey field data, navigation data, processed data, velocity data, observer's logs, operational reports, processing reports, bathymetry data, potential field data (gravity and magnetic) and also hard-copy data submitted during the pre-digital era including seismic sections and other analogue formats <b>Value: </b> Data used for interpreting the geologic structure of the subsurface. This work can be used for the assessment of resource potential. <b>This data can be discovered through the National Offshore Petroleum Information Management System (NOPIMS) - https://www.ga.gov.au/nopims</b>

Australia's CO2CRC Otway Site hosts a carbon capture and storage (CCS) demonstration facility that has, to date, injected over 80,000 tonnes of CO2 into two separate geological reservoirs. The reservoir geology is well understood and the site has been the subject of several seismic investigations, though relatively little is known about the near-surface geology and how potential leaks from the injection wells would migrate, particularly within the Port Campbell Limestone. No shallow core has been taken from relevant petroleum wells or water bores, and although there is extensive exposure in the prominent sea cliffs, these are mostly inaccessible. In order to further define the structure and geology of the Port Campbell Limestone at the Otway site, a high-resolution, shallow focused, 3D seismic survey has recently been conducted. The assessment of the near-surface geology described in this paper was used to assist with planning the survey. Using available data, the Port Campbell Limestone is assessed as a series of laterally continuous intercalated limestone, marl, and marly limestones. Interpretation of three previously acquired 3D seismic surveys using a minimum similarity attribute demonstrates evidence for a shallow, steeply east-dipping fault striking approximately NNW-SSE directly below the Otway site. This is observed from approximately 100 m to 380 m depth below surface, where it appears to die out. In the shallow section, the fault is undetectable primarily due to low seismic resolution, and so it is unknown how shallow it propagates. Extrapolation of the fault to the surface projects to between the wells Naylor-1 and CRC-1. A recently acquired high-resolution 3D seismic survey over the study area will allow for this fault to be further delineated. Appeared in the Energy Procedia Journal, Volume 114, Pages 4424-4435, July 2017