Abstract

The Capel and Faust basins, located on the Lord Howe Rise in water depths between 1,300 m and 2,500 m, were the focus of a series of marine surveys by Geoscience Australia in 2006 and 2007. Their interpretation of high-fold 2D seismic reflection, gravity and magnetic, multi-beam bathymetry, sonobuoy refraction, heat flow and geological sample data suggested the basins have petroleum potential. Analysis of petroleum generation and migration, based on structural maps, lithological and other data supplied by Geoscience Australia, is the focus of this study. Basin models predict that most of the deeper depocentres in the Capel and Faust basins, mapped as containing Jurassic-aged pre-rift and Cretaceous-aged syn-rift source rocks, have the potential to expel oil and gas, and charge nearby syn-rift and post-rift reservoir formations from Cretaceous time to the present day. Multi-1D thermal and petroleum generation models predict: - Pre-rift (215 - 165 Ma) and Syn-rift 1 (130 - 100 Ma) megasequences within the deeper depocentres are within the oil or gas generation window; - Based on the expected presence of petroleum-generative coaly source rocks, total oil and gas expulsion from the major depocentres exceeds 5 MMbbl/km2 and 25 Bcf/km2 respectively from the Pre-rift source rocks, and 20 MMbbl/km2, and 300 Bcf/km2 respectively from the Syn-rift 1 source rocks. In terms of timing, 80% of total hydrocarbon expulsion is predicted by the end of the Eocene, with maximum expulsion taking place between the Late Cretaceous and the Late Eocene (c. 68-36 Ma); - A significant increase in paleo-water depth in late Cenozoic time has supressed further heating related to post-Eocene burial. However, modelling predicts post-Eocene expulsion of oil and gas may have been partly enhanced by post-rift magmatism. In this study total expelled oil and gas volumes are 'migrated across' mapped horizons to assess charge of and fill-spill relationships between structural traps. This map-based charge modelling assumes certain reservoir properties with no migration losses and predicts that: - Accumulations within potential reservoir facies, such as deltaic, shoreline and turbidite sandstones of the lower Post-rift unit (70 - 68 Ma) are dominantly gas with volumes generally about 5 to 9 Tcf at burial depths of 400 - 700 m; - Accumulations within similar sandstones of the upper Syn-rift 2 unit are mixed oil and gas (about 2 to 3 billion bbl oil and 10 Tcf gas) at burial depths of 400 - 800 m; - Similar accumulations are present in the lower Syn-rift 2 and Syn-rift 1 fluvial sands; - Most of the mapped structural traps are buried to relatively shallow depths and seal effectiveness for containment must therefore be a significant risk. Deeper structures and stratigraphic plays may further contribute to the petroleum potential in the basins. The model presented here illustrates the potential for petroleum charge of structural traps in the Capel and Faust basins and highlights the risks associated with source rock distribution and type, reservoir distribution and quality, and seal effectiveness. Volumetric and charge assessments could be further refined using higher density seismic data and appropriate rock property data for reservoir and seal rocks in combination with 3D modelling.
Google map showing geographic bounding box with values North bound -26.0 East bound 163.5 West bound 159.5 South bound -29.5
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please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Product Type/Sub Type

dataset - External Publication - Report

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2011

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

External Publication
Report
hydrocarbons
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-26.0
East bound
163.5
West bound
159.5
South bound
-29.5

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

b3757475-0d8f-60fd-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2011-12-07

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).