Basin Details and Geological Overview
The Gippsland Basin, one of Australia's most prolific hydrocarbon provinces, is situated in southeastern Australia and is located about 200km east of the city of Melbourne. Most of the commercial oil and gas discoveries are reservoired within the siliciclastics of the Late Cretaceous to Paleogene Latrobe Group. Remaining reserves are estimated at 400 MMbbl of liquids and 6 Tcf of gas (unpublished data, Victorian Department of Primary Industries).
A network of pipelines brings produced hydrocarbons to the onshore petroleum processing facilities near Longford. A 457mm (18 inch) gas pipeline from these facilities delivers Gippsland gas along the eastern seaboard of Australia to Sydney in New South Wales. A new network of gas pipelines distributes Gippsland Basin gas to customers in Victoria, Tasmania, New South Wales and South Australia. Increasing gas market demand in the SE Australian region together with deregulation and reform of the upstream and downstream gas industry during recent years has also provided the impetus for renewed exploration activities. This has resulted in an increase in exploration activities in the Gippsland basin with an additional commercial gas discoveries (East Pilchard, Longtom).
|Oil Families||Proven Austral Petroleum Supersystem. Late Cretaceous to Eocene Austral 3 oil population. Three main oil families recognised related to stratigraphic position and in-reservoir alteration. Proven Latrobe- Latrobe system. Also minor contributions from a marine source rock interpreted for some oils.|
|Source||Organic-rich, non-marine, coastal plain shales and coals of the Upper Cretaceous to Early Tertiary Latrobe Group (kerogen Type II/III). Richest source rocks occur within coastal plain and coal swamp facies.|
|Reservoir||Marine nearshore barrier and shoreface sandstones of the Top Latrobe ("coarse clastics") and intra-Latrobe fluvial-deltaic sandstones (Latrobe Siliciclastics). Sandstones in the underlying Golden Beach Subgroup and in the Gurnard Formation channel fill sands unconformably overlying the Latrobe Group.|
|Seal||The Seaspray Group (Lakes Entrance Formation) forms the regional seal. Intra-formational seals present within the Latrobe Group. The reservoirs of the Golden Beach Subgroup are partly sealed by younger volcanics and partly by up-thrown older lacustrine shales of the Emperor Subgroup.|
|Traps||Anticlines, fault closures, erosional remnants, Top Latrobe subcrops.|
|Generation and Timing||Main phase of hydrocarbon expulsion in the Neogene, with earlier phase in the Latest Cretaceous/Paleocene. Trap formation from Cenomanian through to Neogene.|
The Gippsland Basin is geographically restricted (46 000km2), with approximately two-thirds of the basin located offshore. It is bounded to the north by Paleozoic basement of the Eastern Uplands, to the west by uplifted Lower Cretaceous fault-blocks and to the southwest by the Bassian Rise, which separates it from the Bass Basin to the west. In spite of the limited geographic extent of the Gippsland Basin, more than 300 exploration wells have been drilled within it and approximately 90 000 line km of 2D seismic data and more than forty 3D seismic surveys have been acquired. Consequently, exploration within the Gippsland Basin is mature in comparison to other Australian basins, though it is actually relatively under-explored in comparison to many other prolific basins around the world.
As part of the Early Cretaceous rift system between Antarctica and Australia, the Gippsland Basin initial rift architecture consisted of a rift valley complex. Continued rifting into the Late Cretaceous generated a broader depocentre (the Central Deep; flanked by fault-bounded platforms and terraces to the north and south. The Rosedale and Lake Wellington Fault systems marked the northern margin of the Central Deep and Northern Terrace respectively, with the Darriman and Foster Fault systems defining the southern margin of the Central Deep, and the northern boundary of the Southern Platform. To the east, the Central Deep is characterised by rapidly increasing water depths; these exceed 3000 m in the Bass Canyon. The eastern boundary of the basin is defined by the Cape Everard Fault System, a prominent north-northeast-striking basement high. The western onshore extent of the basin is traditionally placed at the Mornington High. However, the Latrobe Group’s extent is effectively defined by the outcrops of the Lower Cretaceous Strzelecki Group.
In the late Eocene, a compressional period began to affect the Gippsland Basin, initiating the formation of a series of northeast to east-northeast-trending anticlines (Smith, 1988). Compression and structural growth peaked in the middle Miocene and resulted in partial basin inversion. All the major fold structures at the top of the Latrobe Group, which became the hosts for the large oil and gas accumulations, such as Barracouta, Tuna, Kingfish, Snapper and Halibut, are related to this tectonic episode.
The Gippsland Basin contains in excess of 10km of Cretaceous to Neogene sediments. The succession is non-marine clastics, to marginal marine clastics, marine clastics and uppermost marine carbonates.
Two regional cross-sections have been selected to provide examples of the regional geometry, distribution, thickness and structural framework of the Gippsland Basin.
Composite seismic cross-sections showing structural and stratigraphic relationships across the Gippsland Basin (after Woollands and Wong, 2001)
© Geoscience Australia
Gippsland Basin - Seismic section across the Gippsland Basin (after O'Brien et al., 2007)
© Geoscience Australia
|Bernecker, T. and Partridge, A.||2005||Approaches to Palaeogeographic Reconstructions of the Latrobe Group, Gippsland Basin, Southeastern Australia. The APPEA Journal, Vol: 45, Issue 1, pp. 581–600|
|O’Brien, G.W., Tingate, P. R., Goldie Divko, L.M., Harrison, M.L., Boreham, C.J., Liu, K., Arian, N. and Skladzien, P.||2008||First Order Sealing and Hydrocarbon Migration Processes, Gippsland Basin, Australia; Implications for CO2 Geosequestration. IN: Blevin, J.E., Bradshaw, B.E. and Uruski, C. (eds), Eastern Australasian Basins Symposium III, Petroleum Exploration Society of Australia, Special Publication, pp. 1–28|
|Messent, B. E. J. and Farmer, L. E.||2008||Basker Field, Gippsland Basin: Assessing Reservoir Connectivity with the Aid of Complementary Technologies. IN: Blevin, J.E., Bradshaw, B.E. and Uruski, C. (eds), Eastern Australasian Basins Symposium III, Petroleum Exploration Society of Australia, Special Publication, pp. 29–44|
|Alexander, R., Kagi, R.I., Woodhouse, G.W. and Volkman, J.K.||1983||The Geochemistry of some Biodegraded Australian Oils. The Australian Petroleum Production & Exploration Association (APEA) Journal, Vol. 23 Issue 1, pp. 53-63.|
|Bernecker, T. and Partridge, A.D.||2001||Emperor and Golden Beach Subgroups: The onset of Late Cretaceous Sedimentation in the Gippsland Basin, SE Australia. IN: Hill, K.C. & Bernecker, T. (Editors) Eastern Australasian Basins Symposium, Petroleum Exploration Society of Australia, Special Publication, pp. 391-402|
|Bernecker, T., Woollands, M.A., Wong, D., Moore, D.H. and Smith, M.A.||2001||Hydrocarbon Prospectivity of the Deep-water Gippsland Basin, Victoria, Australia. The APEA Journal, Vol: 41 Issue 1, pp.79-101|
|Brooks, J.D. and Smith, J.W.||1969||Coalification and the Formation of Oil and Gas in the Gippsland Basin. Geochemica et Cosmochimica Acta, Vol: 33, pp. 1183-1194|
|Burns, B.J., James, A.T. and Emmett, J.K.||1984||The Use of Gas Isotopes in Determining the Source of Some Gippsland Basin Oils. The APEA Journal, Vol: 24 Issue 1, pp. 217-221|
|Clark, A.B.S. and Thomas, B.M.||1988||The Intra-Latrobe Play: A Case History from the Basker/Manta Block (VIC/P19), Gippsland Basin. The APEA Journal, Vol: 28 Issue 1, pp. 100-112|
|Cousins, M.G.||1995||Geophysical Optimisation of the Mackerel Field Re-development - Gippsland Basin, Australia. The APPEA Journal, Vol: 35 Issue 1, pp. 79-91|
|Geoscience Australia and Geomark Research||2002||The Oils of Eastern Australia. Unpublished proprietary report, Canberra and Houston|
|Gorter, J.D.||2001||A Marine Source Rock in the Gippsland Basin? IN: Hill, K.C. & Bernecker, T. (Editors) Eastern Australasian Basins Symposium, Petroleum Exploration Society of Australia, Special Publication, pp. 385-390|
|Hinton, P.V., Cousins, M.G. and Symes, P.E.||1994||The Integration of Modern Technology in Gippsland's Central Fields Study. The APPEA Journal, Vol: 34 Issue 1, pp. 513-852|
|James, E.A. and Evans, P.R.||1971||The Stratigraphy of the Offshore Gippsland Basin. The APEA Journal, Vol: 11, pp. 71-74|
|MIM Petroleum Exploration Pty Ltd||1995||VIC/P33 Relinquishment Report, August 1995, Report No. MIM 152 (unpublished).|
|Moore, D.H. and Wong, D.||2001||Down and Out in Gippsland: Using Potential Fields to Look Deeper and Wider for New Hydrocarbons. IN: Hill, K.C. & Bernecker, T. (Editors) Eastern Australasian Basins Symposium, Petroleum Exploration Society of Australia, Special Publication, pp. 363-371|
|Mudge, W.J. and Curry, J.J.||1992||Development Opportunities in the Kingfish and West Kingfish Fields, Gippsland Basin. The APPEA Journal, Vol: 32 Issue 1, pp. 9-18|
|Norvick, M. and Smith, M.A.||2001||Mapping the Plate Tectonic Reconstructions of Southern and Southeastern Australia and Implications for Petroleum Systems. The APPEA Journal, Vol: 41 Issue 1, pp. 15-35|
|O'Brien, G.W., Bernecker, T., Thomas, J.H., Driscoll, J., Harrison, M. and Frankel, E.||2007||Hydrocarbon Prospectivity of Areas V07-1, V07-2 and V07-3, Northeastern Offshore Gippsland Basin, Victoria, Australia. VIMP Report 92, Department of Primary Industries|
|Rahmanian, V.D., Moore, P.S., Mudge, W.J. and Spring, D.E.||1990||Sequence Stratigraphy and the Habitat of Hydrocarbons, Gippsland Basin. - IN: Brooks, J. (Editor), Classic Petroleum Provinces, Geological Society Special Publication No. 50, pp. 525-541|
|Smith, M.A.||1999||Petroleum Systems, Play Fairways and Prospectivity of the Gazettal Area V99-2, Offshore Southern Gippsland Basin, Victoria. Victorian Initiative for Minerals and Petroleum Report 61, Department of Natural Resources and Environment|
|Smith, M.A., Bernecker, T., Liberman, N., Moore, D.H. and Wong, D.||2000||Petroleum Prospectivity of the Deepwater Gazettal Areas V00-3 and V00-4, Southeastern Gippsland Basin, Victoria, Australia. Victorian Initiative for Minerals and Petroleum Report 65, Department of Natural Resources and Environment|
|Volk, H., George, S.C., Lisk, M., Killops, S.D., Ahmed, M. and Quezada, R.A.||2001||Charge Histories of Petroleum Reservoirs in the Gippsland and Taranaki Basins - Evidence from the Analysis of Oil Inclusions and Crude Oils. IN: Hill, K.C. & Bernecker, T. (Editors) Eastern Australasian Basins Symposium, Petroleum Exploration Society of Australia, Special Publication, pp. 413-422|
|Wilcox, J.B., Colwell, J.B. and Constantine, A.E.||1992||New Ideas on Gippsland Basin Regional Tectonics. IN: C.M. Barton, K. Hill, C. Abele, J. Foster & N. Kempton, (Editors), Energy, Economics and Environment Gippsland Basin Symposium, pp. 93-110, (Australasian Institute of Mining & Metallurgy, Melbourne Branch)|
|Wong, D. and Bernecker, T.||2001||Prospectivity and Hydrocarbon Potential of Area V01-4, Central Deep, Gippsland Basin, Victoria, Australia: 2001 Acreage Release. Victorian Initiative for Minerals and Petroleum Report 67, Department of Natural Resources and Environment|
|Woollands, M. A. and Wong, D. (Editors),||2001||Petroleum Atlas of Victoria, Australia. Department of Natural Resources and Environment, Victoria|