shallow water area (Nerita-1, Snail-1 and Wild Dog-1)
Gas Fields to the west
(Minerva and Port Campbell Gas Fields)
Gas shows in the Cretaceous
units in Nerita-1
source rocks and trapping potential in deeper stratigraphic units
In this study, the thermal,
structural and hydrocarbon generation history of the area is assessed
using AFTA and VR data to identify, quantify and characterise the paleo-thermal
episodes which have affected the region, particularly key episodes of
heating during the Mesozoic and Tertiary.
The Torquay Sub-Basin study area covers the V99-1 Gazettal
Block in the eastern part of the offshore Otway Basin. The Early Cretaceous
section in the Otway basin contains proven oil and gas source intervals
but drilling to date in V99-1 has failed to prove oil and gas in commercial
quantities. However, the region is underexplored, and given the close
proximity of the gas markets of eastern Australia (and established infra-structure)
the acreage warrants further investigation. The principal source rocks
are within the Eumeralla, Pretty Hill and Casterton Formations, with
gas being the most likely hydrocarbon type.
The complicated tectonic history of the region, and
its profound influence on the thermal history of the potential source
horizons, has not been fully considered in past exploration programs,
and hence the hydrocarbon maturation and generation history is poorly
Application of AFTA and VR data has allowed a complex
thermal history to be unravelled, including the identification and quantification
of key episodes of heating during the Mesozoic and Tertiary. These data
are critical to the understanding of maturation and the timing of episodes
of hydrocarbon generation relative to structural development.
The report will be of value to those companies assessing
AREA V99-1, companies evaluating the potential of the onshore Otway
Basin region and those with wider interests in the hydrocarbon generation
history of the adjacent offshore Otway, Sorell and Bass Basins.
Specific objectives of this Geotrack study include:
timing and amounts of uplift and erosion
regional assessment of hydrocarbon generation history
maximum paleotemperatures and their timing
constraints on paleogeothermal gradients
dominant thermal episodes relevant to prospectivity
The project is based on new and open-file AFTA and
VR analyses from:
the three offshore wells: Wild
Dog-1, Snail-1 and Nerita-1
and the onshore wells:
Anglesea-1, Olangolah-1 and Hindhaugh Creek-1
The study is a comprehensive report in two volumes.
Volume 1 will provide full details of the thermal history interpretation
of AFTA and VR data from each well, while all AFTA and VR data plus
supporting geological information will be presented in four Appendices
in Volume 2. The main conclusions of the study will be presented in
an Executive Summary with accompanying summary diagrams and tables.
Full details of analytical techniques and information on data quality
will also be provided.
Project available July 26th 1999
For further information, please contact