Geological interpretation of seismic reflection lines 08GA-A1 and 09TE-01: Arrowie Basin, South Australia L.K. Carr 1, R.J. Korsch 1, J. Holzschuh 1, Geological R.D. interpretation Costelloe 1, A.J. Meixner of 1, seismic reflection lines C. Matthews 08GA-C1 2 and B. Godsmark and 3 09TE-01: Arrowie Basin, South Australia 1 Onshore Energy & Minerals Division, GPO Box 378, Canberra, ACT 2601, Australia 2 Torrens Energy Limited, PO Box 506, Unley, SA 5061, Australia 3 Formerly Torrens Energy Limited, PO Box 506, Unley, SA 5061, Australia
Acknowledgements Primary Industries and Resources South Australia (PIRSA) Torrens Energy Limited
Outline Onshore Energy Security Program (OESP) Arrowie Basin geological context 08GA-A1 Line Forward Model 09TE-01 Line Conclusions
Onshore Energy Security Program Precompetitive geoscience data and assessments Deep seismic reflection data acquired across frontier sedimentary basins Arrowie Basin: SANTOS, drilling encountered non-commercial bituminous hydrocarbons in the Cambrian succession Cambrian oil generation, in some places still within the oil generation-preservation window (McKirdy, 1994)
The Arrowie Basin Intracratonic basin Cambrian sediments underlain by Neoproterozoic Five major structural components Post-rift thermal subsidence Deposition ceased with onset of Delamerian Orogeny (~500 Ma)
Line Locations.
Stuart Shelf and Torrens Hinge Zone Neoproterozoic and Cambrian sediments deposited on Stuart Shelf (SS) SS overlies the NE part of the Gawler Craton Torrens Hinge Zone is area of sediment thickening and deformation to east of SS Transition zone to the MUCH thicker outcrop of the Flinders Ranges
Time Ma. Lake Frome Group Hawker Group Wilpena Group Umberatana Group Delamerian Orogeny 500 Ma Tuffs in Billy Creek Fm/ Hawker 522Ma, 526Ma (Zang, 2002) Arrowie Basin Wilpena Group 550-545Ma Adelaide Rift System Glacial 572-586Ma (Giddings et al, 2009) Glacial 643-660 Ma (Giddings et al, 2009) Arrowie Basin and Neoproterozoic Succession Burra Group Callanna Group 790 Ma (W.Preiss) 825 Ma (W.Preiss)
Seismic line 08GA-A1 2008 GA (OESP) and PIRSA acquired 60 km deepseismic line (08GA-A1) across western part of Arrowie Basin Asymmetrical basin Sediment pile 700m deep in west to 3800m in east on this seismic transect Limited geological control Wilkatana wells 15 km to south
08GA-A1 0-20 s (TWT) ~ 60 km @ 6 km s -1
08GA-A1 (20 s) Moho poorly defined Mid crust reflective Weakly reflective crust below basin GRV interpreted below basin
08GA-A1 (3 s) Yadlamalka Fault Nob Hill Fault Base Cenozoic Base Hawker Group Base Wilpena Group Base Umberatana Group Base Burra Group Base Callanna Group Base Pandurra Formation Gawler Range Volcanics
08GA-A1 Yadlamalka Fault TDKH1A 08GA-A1 Drill hole TDKH1A intersected Cenozoic sediments, Callanna Group, then the Yadlamalka Fault, followed by younger (Wilpena Group) sediments
08GA-A1 Torrens Hinge Zone zoom Sediment thickening and deformation increases to the east Wilkatana Fault to east of section
GRV Wilkatana Range front Bonney Sandstone Rawnsley Quartzite Pandurra Formation
Seismic Line 09TE-01 In 2009, Torrens Energy Limited acquired 41 km seismic line (09TE-01) at Parachilna Succession thicker than 08GA-A1 section, 3500-5800m Thicker Cambrian succession preserved Thicker Cenozoic section High heat flow measurements
T G M
2000 2500 3000 3500 4000
2000 Treebeard 2500 3000 Gollum 3500 4000
09TE-01 Ediacara Fault Quaternary displacement on Ediacara Fault Frontal thrust to western Flinders Ranges
09TE-01(eastern end) Torrens Hinge Zone Gollum
09TE-01 41 km 2500 3500 08GA-A1 60 km V:H=2:1
Conclusion Relatively undeformed stratigraphic succession on Stuart Shelf THZ thickened sedimentary pile plus faults and related folds Faults cut Cambrian Succession Delamerian movement Quaternary movement Petroleum maturation modelling in progress GRV
Thank you