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Australian Energy Producers Journal Australian Energy Producers Journal Society
Journal of Australian Energy Producers
RESEARCH ARTICLE (Non peer reviewed)

Dorado discovery – unlocking a major new oil and gas play in the Bedout Sub-basin

Melissa Thompson
+ Author Affiliations
- Author Affiliations

Santos Limited, Level 7, 100 St Georges Terrace, Perth, WA 6000, Australia. Email: melissa.thompson@santos.com

The APPEA Journal 60(2) 778-783 https://doi.org/10.1071/AJ19128
Accepted: 4 April 2020   Published: 15 May 2020

Abstract

In 2014, Santos (formerly Apache and Quadrant Energy Limited) acquired an operated exploration position over most of the under-explored Bedout Sub-basin. A multi-year exploration program was subsequently executed, targeting plays within Middle Triassic fluvio-deltaic sediments of the Lower Keraudren and Archer formations. Initial wells at Phoenix South and Roc established the presence of high-quality reservoirs, source rocks and hydrocarbon fluids, but the commerciality of these discoveries was impeded by the lack of existing production infrastructure in this frontier basin. In 2018, Santos and its Joint Venture partner, Carnarvon Petroleum, drilled Dorado-1, targeting stacked Archer Formation reservoirs in an erosional truncation trap set up by a major canyon system. The well encountered light oil and/or condensate rich gas in high-quality reservoir sands at each of the target intervals. Despite limited well control, burial depths on the order of 4000 m and imperfect seismic data, the pre-drill prognosis was remarkably accurate, largely due to the application of modern seismic inversion techniques. Subsequent appraisal drilling undertaken during 2019 demonstrated the discovery is larger than originally anticipated and has significantly de-risked a future development. New seismic acquired during 2019 will be used to further improve the understanding of Dorado reservoirs and to mature follow-up prospects for future drilling.

Keywords: Archer Formation, Baxter Member, Caley Member, Crespin Member, Lower Keraudren Formation, Milne Member.

Melissa Thompson has more than 28 years of experience in the petroleum industry with independent exploration and production companies in both Australia and internationally, working a variety of basins. With a broad exploration skill set, she has led successful exploration teams in opening new plays and petroleum systems on the NWS and in North Africa. She has held various roles with Apache/Quadrant/Santos since joining in 2001 and has been Exploration Manager for the Bedout area since 2014. Melissa holds a Bachelor of Science degree (Petroleum Geology Hons I) from Sydney University, Australia and is a member of PESA.


References

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Kongawoin, M., Pauli, A., Locke, A., and Hansen, L. (2019). Quantitative Interpretation in the Bedout Sub-basin: The value of seismic inversion in areas of sub-optimal seismic data quality. In ‘The Sedimentary Basins of Western Australia V: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 15–22 November 2019.’ (Eds M. Keep and S. J. Moss.) p. 17 (PESA: Perth, WA).

Minken, J., Thompson, M., Woodward, J., and Fabrici, R. (2018). Tectonostratigraphic framework of the Lower Keraudren Formation, Bedout Sub-basin: interplay of tectonics and sedimentary systems. The APPEA Journal 58, 839–844.
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Thompson, M., Wehr, F., Woodward, J., Minken, J., D’Orazio, G., Fernandes, F., Kongowoin, M., Hansen, L., Kuek, D., and Fabrici, R. (2018). Recent exploration results in the Lower Triassic, Bedout Sub-basin – Australia’s Next Petroleum Province? The APPEA Journal 58, 871–877.
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Woodward, J., Minken, J., Kongawoin, M., Hansen, L., Thompson, M., and Fabrici, R. (2018). The Lower Triassic Caley Member: depositional facies, reservoir quality and seismic expression The APPEA Journal 58, 878–883.
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