Changes

The limits of the Beetaloo Sub-basin have been recently updated and formalized by the Northern Territory Geological Survey and have been constrained using lithostratigraphic data from 26 wells tied to stratigraphic interpretations of 96 seismic surveys. Accordingly, the sub‑basin boundary is currently defined using the top of the Kyalla Formation (Roper Group), constrained by a cut-off depth of 400 m below surface<ref>Williams, B., 2019, Definition of the Beetaloo Sub basin: Northern Territory Geological Survey, Record 2019 01</ref>. It is important to note that the current geophysical definition does not correspond to the extent of sediments of interest for hydrocarbon exploration and hydrocarbon plays have been identified beyond the extents of the geophysically defined boundary<ref>Bruce, A., and D. Garrad, 2021, Unlocking the eastern extension of the Beetaloo Sub-basin middle Velkerri shales: Annual Geoscience Exploration Seminar (AGES) Proceedings, Alice Springs, Northern Territory 20-21 April 2021, p. 37.</ref>.

The limits of the Beetaloo Sub-basin have been recently updated and formalized by the Northern Territory Geological Survey and have been constrained using lithostratigraphic data from 26 wells tied to stratigraphic interpretations of 96 seismic surveys. Accordingly, the sub‑basin boundary is currently defined using the top of the Kyalla Formation (Roper Group), constrained by a cut-off depth of 400 m below surface<ref>Williams, B., 2019, Definition of the Beetaloo Sub basin: Northern Territory Geological Survey, Record 2019 01</ref>. It is important to note that the current geophysical definition does not correspond to the extent of sediments of interest for hydrocarbon exploration and hydrocarbon plays have been identified beyond the extents of the geophysically defined boundary<ref>Bruce, A., and D. Garrad, 2021, Unlocking the eastern extension of the Beetaloo Sub-basin middle Velkerri shales: Annual Geoscience Exploration Seminar (AGES) Proceedings, Alice Springs, Northern Territory 20-21 April 2021, p. 37.</ref>.

The sub‑basin is of considerable economic interest as a potential host for unconventional and conventional petroleum resources, particularly in the uppermost Roper Group where stacked play opportunities include liquids rich shale, dry gas shale and hybrid/ tight gas plays (Côté et al. 2018; Altmann et al., 2020). Prospective units for gas and liquids resources have been identified in the organic rich [[mudstones]] of the Kyalla Formation and Velkerri Formation of the Mesoproterozoic Roper Group and the latter is the most technically mature resource play in the Beetaloo.

The sub‑basin is of considerable economic interest as a potential host for unconventional and conventional petroleum resources, particularly in the uppermost Roper Group where stacked play opportunities include liquids rich shale, dry gas shale and hybrid/ tight gas plays<ref>Côté, A., B. Richards, C. Altmann, E. Baruch, and D. Close, 2018, Australia’s premier shale basin: five plays, 1,000,000,000 years in the making: The APPEA Journal, vol. 58, no. 2, p. 799-804.</ref><ref>Altmann, C., B. Richards, A. Côté, C. Bein, E. Baruch-Jurado, and L. Jenkinson, 2020, The Hayfield Sandstone Play: the characterisation of a Mesoproterozoic sourced, Proterozoic sandstone reservoired, tight oil and gas play in the Beetaloo Sub-basin: The APPEA Journal, vol. 60, no. 1, p. 242-266.</ref>. Prospective units for gas and liquids resources have been identified in the organic rich [[mudstones]] of the Kyalla Formation and Velkerri Formation of the Mesoproterozoic Roper Group and the latter is the most technically mature resource play in the Beetaloo.

Despite its age, the Velkerri Formation is remarkably well preserved and relatively undisturbed, it is a fine-grained unit mostly constituted of siliceous mudstone, siltstone and minor sandstone lithologies. It is rarely exposed and most of its characterization is based on drill cores of various vintages. The nominated type section has been cored in drillhole Urapunga-4 from 372 m to 42 m of depth and the core is stored in the National Offshore Petroleum Data & Core Repository at Geoscience Australia in Canberra (Munson 2016), maximum known thickness is 1483 m reported in well Tanumbirini-1. Based on core facies association, presence of glauconite and acritarchs, the depositional environment of the formation is interpreted as marine below wave base, in a distal outer shelf or slope setting (Munson 2016).

Despite its age, the Velkerri Formation is remarkably well preserved and relatively undisturbed, it is a fine-grained unit mostly constituted of siliceous mudstone, siltstone and minor sandstone lithologies. It is rarely exposed and most of its characterization is based on drill cores of various vintages. The nominated type section has been cored in drillhole Urapunga-4 from 372 m to 42 m of depth and the core is stored in the National Offshore Petroleum Data & Core Repository at Geoscience Australia in Canberra (Munson 2016), maximum known thickness is 1483 m reported in well Tanumbirini-1. Based on core facies association, presence of glauconite and acritarchs, the depositional environment of the formation is interpreted as marine below wave base, in a distal outer shelf or slope setting (Munson 2016).

==References==

==References==

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* Bodorkos, S., Crowley, J.L., Claoué-Long, J.C., Anderson, J.R. and Magee Jr, C.W., 2020. Precise U–Pb baddeleyite dating of the Derim Derim Dolerite, McArthur Basin, Northern Territory: old and new SHRIMP and ID-TIMS constraints. Australian Journal of Earth Sciences, pp.1-15.

* Bodorkos, S., Crowley, J.L., Claoué-Long, J.C., Anderson, J.R. and Magee Jr, C.W., 2020. Precise U–Pb baddeleyite dating of the Derim Derim Dolerite, McArthur Basin, Northern Territory: old and new SHRIMP and ID-TIMS constraints. Australian Journal of Earth Sciences, pp.1-15.

* Close, D., Côté, A., Baruch, E., Altmann, C., Mohinudeen, F., Richards, B., Ilett, R., Evans, R. and Stonier, S., 2017. Exploring the Beetaloo: will Australia’s first viable shale play be sourced by billion year old gas?. The APPEA Journal, 57(2), pp.716-721.

* Close, D., Côté, A., Baruch, E., Altmann, C., Mohinudeen, F., Richards, B., Ilett, R., Evans, R. and Stonier, S., 2017. Exploring the Beetaloo: will Australia’s first viable shale play be sourced by billion year old gas?. The APPEA Journal, 57(2), pp.716-721.

 

* Delle Piane, C., Uysal, I.T., Faiz, M., Pan, Z., Bourdet, J., Li, Z., Raven, M.D. and Dewhurst, D.N., 2020. Thermal maturity and reservoir quality of the Velkerri Formation, Beetaloo Sub-basin, Northern Territory. The APPEA Journal, 60(2), pp.697-702.

* Delle Piane, C., Uysal, I.T., Faiz, M., Pan, Z., Bourdet, J., Li, Z., Raven, M.D. and Dewhurst, D.N., 2020. Thermal maturity and reservoir quality of the Velkerri Formation, Beetaloo Sub-basin, Northern Territory. The APPEA Journal, 60(2), pp.697-702.

* Faiz, M., Altmann, C., Dunne, M., Baruch, E., Close, D., Cote, A., Richards, B. and Ranasinghe, P., 2016, June. Precambrian organic matter and thermal maturity of the Beetaloo Basin, Northern Territory, Australia. In Australian Earth Sciences Convention, Adelaide, South Australia (pp. 26-30).

* Faiz, M., Altmann, C., Dunne, M., Baruch, E., Close, D., Cote, A., Richards, B. and Ranasinghe, P., 2016, June. Precambrian organic matter and thermal maturity of the Beetaloo Basin, Northern Territory, Australia. In Australian Earth Sciences Convention, Adelaide, South Australia (pp. 26-30).