Otway Basin Petroleum Systems Model 2023

Aim

The aim of this project was to generate new datasets and new exploration concepts to stimulate the next phase of gas exploration in the onshore Otway Basin to supply South Australian customers. Outputs from the project also provide insights into the potential for Carbon Capture and Storage and underground hydrogen storage in the basin.

Introduction

Figure 1. Otway Basin (SA) location map with tenements.

The Otway Basin is one of the best known Mesozoic rift basins that span the southern coastline of Australia and has both on and offshore gas production and oil discoveries (Fig. 1). 104 petroleum and 6 geothermal wells have drilled since the 1890s. In 1987 Katnook 1 discovered economic gas in the Penola Trough (the most significant hydrocarbon province in the SA part of the basin to date), further drilling led to more discoveries and construction of a processing plant. The modern Katnook Gas Plant (currently mothballed) has improved the economic viability of small gas discoveries to fuel both local gas markets and electricity generation. The SA Otway Basin is strategically connected to local southeast and Statewide natural gas customers by the SEA Gas and SESA pipelines (Fig. 1).

Outcome

Petroleum system modelling (PSM), based on extensive, source rock, well and seismic investigation, shows, for the first time, significant oil and gas generation and expulsion in the lightly explored Robe and Tantanoola Troughs (Fig 2).

Figure 2. Modelled gas expulsion map onshore Otway Basin in South Australia (JPG 10 MB)

Product downloads

Project summary

• Brochure: A fresh look at the South Australian onshore Otway Basin (PDF 9.1 MB)

Core

What's included:

• Core Logs (Excel)
• Core Logs (Plots)

View metadata and download core package

DE-GDE

What's included:

• Depositional environment and gross depositional environment diagrams and maps (JPG and PDF)

View metadata and download DE-GDE package

Source rock geochemistry

What's included:

• 1D Modelling
• Model exports
• Petrosys maps
• Source rock logs
• T3 Modelling (Trinity project)

View metadata and download source rock geochemistry package

Mapping projects

• View metadata and download ESRI ArcGIS project (.mpk)
• View metadata and download Petrosys project

Seismic

What's included:

• Two-way time grids
• Depth grids
• Isopachs (for GDE mapping)
• Difference maps
• Extent polygons (.shp)

View metadata and download seismic package

Stratigraphy

• Updated stratigraphic chart (PDF 63 KB)
• Updated stratigraphic chart (JPG 584 KB)

Publications

Bendall, B., Forbes, A.B., Revie, D.C., Eid, R.C., Herley, C. and Hill, A.J., 2020, New insights into the stratigraphy of the Otway Basin. The APPEA Journal 60(2) 691-696

Bendall, B., Forbes, A. and Hill, A.J. 2021. Resolving lithostratigraphic complexities in the Crayfish Group, Otway Basin using chemostratigraphy. The APPEA Journal 61(2) 588-593

Hill, A.J., Bendall, B. and Murray, A. 2020, New insights into the organic geochemistry of the Otway Basin. The APPEA Journal 60(2) 712-717

For more information please contact us at DEM.Petroleum@sa.gov.au.