Authors / CoAuthors
Gunning, M. | Nicholson, C.
Abstract
Geoscience Australia has undertaken a regional seismic mapping study of the offshore Otway Basin extending across the explored inner basin to the frontier deep-water region. Seismic interpretation covers over 18,000 line-km of new and reprocessed data acquired in the 2020 Otway Basin seismic program, over 40,000 line-km of legacy 2D seismic data and GA’s new 2023 Otway 3D post-stack Mega Merge seismic dataset. This work provides a new perspective on regional structural architecture and basin evolution and has important implications for hydrocarbon prospectivity of this region. This seminar was two short talks centring on the Otway Basin. <u>Post-stack 3D merging to fast-track regional interpretation - offshore Otway Basin case study, presented by Merrie-Ellen Gunning</u> This case study was to produce a regularised and seamless 3D dataset of the highest possible quality, for the offshore Otway Basin, within two-months. The input migrated volumes varied by data extent, migration methodology, angle range and grid orientation. Fourteen 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. A mis-tie analysis algorithm, applied over a time window optimised for interpretation of key events, was used to derive corrections for timing, phase and amplitude, using a reference. This was followed by time-variant spectral and amplitude matching 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 events and dramatically improving the efficiency and quality of interpretation. This enables rapid reconnaissance of the area by explorers. <u>Structural architecture of the offshore Otway Basin presented by Chris Nicholson</u> We present new basin-scale isochore maps that show the distribution of the Cretaceous depocentres. Maps for the Lower Cretaceous Crayfish and Eumeralla supersequences, together with those recently published for the Upper Cretaceous Shipwreck and Sherbrook Supersequences, completes the set of isochore maps for the main tectonostratigraphic basin intervals. Mapping of basement involved faults has revealed structural fabrics that have influenced depocentre development. The tectonostratigraphic development of depocentres and maps of deep crustal units delineate crustal thinning trends related to late Cretaceous extension phases. This work highlights the need to review and update structural elements. For example, the boundary between the Otway and Sorell basins is now geologically constrained. The refinements to the tectonostratigraphic evolution of the Otway Basin presented here have important implications for the distribution and potential maturity of petroleum systems, especially with regard to heat flow associated with crustal extension.
Product Type
document
eCat Id
149528
Contact for the resource
Resource provider
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Point of contact
Digital Object Identifier
Keywords
- ( Project )
-
- Offshore Otway Basin study
-
- Otway Basin
-
- structural architecture
-
- sequence stratigraphy
-
- hydrocarbon prospectivity
-
- Wednesday Seminar
-
- Outreach
- theme.ANZRC Fields of Research.rdf
-
- Structural geology and tectonicsSedimentologyResource geoscience
-
- Published_External
Publication Date
2024-06-14T04:45:42
Creation Date
Security Constraints
Legal Constraints
Use - license otherRestrictions
Status
completed
Purpose
The purpose of this presentation is to promote the recent precompetitive geoscience work in the offshore Otway Basin to industry stakeholders at the Australian Energy Producers conference. The secondary purpose is to the share this presentation with a GA audience at a Wednesday seminar.
Maintenance Information
asNeeded
Topic Category
geoscientificInformation
Series Information
The Australian Energy Producers Journal
Lineage
<div>This presentation was created to promote an extended abstract published at the Australian Energy Producers conference in Perth in May 2024. The presentations was then to be presented as a GA seminar in June 2024.</div>
Parent Information
Extents
[-44, -9, 112, 154]
Reference System
Spatial Resolution
Service Information
Associations
Source Information