VMPi VIICTORIAN NITIATIVE FMOR INERALS &P ETROLEUM HYDROCARBON P ROSPECTIVITY P ACKAGE F OR VIC/O-01(1), VIC/O-01(2) andVIC/O-01(3) , E ASTERN O NSHORE O TWAY B ASIN, VAICTORIA, USTRALIA: 2001 ACREAGE R ELEASE VIMP REPORT 70 A.E. CONSTANTINE N. LIBERMAN November 2001 KYNETON PEP160 BALLARAT AREA OF INTEREST HAMILTON MELBOURNE PEP151 PEP150 LARA PEP159 GEELONG VIC/O-01(1) VIC/O-01(3) PEP152 (b) COBDEN 200m COLAC PORTLAND PEP154(a) VIC/P46 1000m PEP153 VIC/O-01(2) VIC/P44 2000m 3000m VIC/P43 0 10 20 30 40 50 Km 4000m 2001 acreage release . VIMP Report 70 Hydrocarbon prospectivity package for VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3), Eastern Onshore Otway Basin, Victoria, Australia 2001 Acreage Release A. Constantine and N. Liberman November 2001 Bibliographic reference: CONSTANTINE, A. and LIBERMAN, N., 2001. Hydrocarbon Prospectivity Package for VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3), Eastern Onshore Otway Basin, Victoria, Australia. 2001 Acreage Release. Victorian Initiative for Minerals and Petroleum Report 70. Department of Natural Resources and Environment. © Crown (State of Victoria) Copyright 2001 Petroleum Development ISSN 1323 4536 ISBN 0 7306 9472 0 (Hard Copy) ISBN 0 7306 9473 9 (CD-ROM) This report may be purchased from: Business Centre Minerals & Petroleum Department of Natural Resources and Environment 8th Floor, 240 Victoria Parade East Melbourne, Victoria 3002, Australia For further technical information contact: Manager Petroleum Development Department of Natural Resources and Environment PO Box 500 East Melbourne, Victoria 3002, Australia Website: www.nre.vic.gov.au/minpet/index.htm Authorship and Acknowledgments: The package was compiled and collated by the Basin Studies Group of the Petroleum Development Unit. The authors would like to acknowledge the following Petroleum Development Unit staff members for their assistance in the production of this report: David Wong, Eddie Frankel, Mike Woollands, Jim Driscoll and Laiyee Mok. Disclaimer: This publication may be of assistance to you but the authors and the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. PROSPECTIVITY OF EASTERN ONSHORE OTWAY BASIN 1 Contents Executive Summary 4 1 Introduction 5 2 Exploration History 10 3 Basin Development 13 4 Structural Elements 15 4.1 Late Jurassic – Early Cretaceous (Tithonian – Barremian) 15 Gellibrand Trough 15 Ombersely Trough 15 Armytage High 15 Stoneyford High 15 4.2 Mid-Cretaceous 15 Otway Uplift 15 Warracbarunah Uplift 15 4.3 Upper Late Cretaceous – Tertiary 15 Colac Trough 15 Barwon Downs Graben 16 Anglesea Embayment 16 Torquay Sub-basin 16 Sorrento Graben 16 4.4 Late Tertiary (Late Miocene – Pliocene) 16 Otway Ranges 16 Barongarook High 16 Barrabool Hills 16 Paraparap High 16 Bellarine High 17 5 Stratigraphy 23 5.1 Otway Group 23 5.2 Sherbrook Group 23 5.3 Wangerrip Group/Eastern View Group 27 Wangerrip Group 27 Eastern View Group 27 5.4 Nirranda Group/Demons Bluff Group 29 Nirranda Group 29 Demons Bluff Group 29 5.5 Heytesbury Group/Torquay Group 29 Heytesbury Group 29-30 Torquay Group 30 5.6 Older Volcanics 30 5.7 Newer Volcanics 30 6Seismic Data 31 6.1 Seismic Coverage 31 VIC/O-01(1) 31 VIC/O-01(2) 31 VIC/O-01(3) 31 6.2 Seismic Interpretation and Mapping 32 TWT Structure Maps 32 Interpreted Seismic Sections 32 7 Other Geophysical Data 33 7.1 Gravity 33 7.2 Magnetics 33-34 2 PROSPECTIVITY OF EASTERN ONSHORE OTWAY BASIN 8 Petroleum Systems 35 8.1 Casterton Formation – Pretty Hill Formation 35 8.2 Eumeralla Formation 35-36 9 Maturation History 38 10 Play Fairways and Play Types 41 10.1 Fractured Basement 41 10.2 Pretty Hill Formation 41 10.3 Intra-Eumeralla Formation 43 Heathfield Sandstone 43 Barwon River Member 43 10.4 Base Tertiary 45 Pebble Point Formation 45 Moomowroong Sand – Wiridjil Gravel 45 Eastern View Formation 45 11 Summary 47 11.1 VIC/O-01(1) 47 11.2 VIC/O-01(2) 47 11.3 VIC/O-01(3) 47-48 12 Natural/Cultural Environments and Regulations 49 12.1 Primary Petroleum Legislation 49 12.2 Access to land 49 Open-File Reports available from MPV 50-52 CD-ROM Data Packages available from MPV 53 References 54-57 MPV Contacts 58 Victorian Initiative for Minerals and Petroleum (VIMP) report series 59-60 List of Figures 1. Petroleum exploration wells in and around VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3). Seismic 7 lines in the three blocks are coloured grey. A – A’ is the location of the schematic regional cross-section illustrated in Figure 5. 2. Pipeline infrastructure. 8 3. Geological maps issued by Geological Survey of Victoria covering the Eastern Otway Basin. 9 4. Tectonic history of the Otway Basin (from Geary & Reid, 1998). 14 5. Regional cross-section across the Eastern Otway Basin (modified from Messent et al., 1999). 18 6. Late Jurassic – Early Cretaceous (Tithonian – Barremian) structural elements in VIC/O-01(1), 19 VIC/O-01(2) and VIC/O-01(3). Colour-fill grid is a TWT structure map of Top Basement. 7. Mid-Cretaceous denudation map for the Eastern Otway Basin (modified from Cooper & Hill, 1997). 20 Contour values in metres. 8. Surface structure map of the Eastern Otway Basin showing the main Late Cretaceous – Tertiary 21 depocentres and key Late Miocene – Pliocene faults, monoclines, anticlines and synclines. 9. Late Miocene – Pliocene denudation map for the Eastern Otway Basin (modified from 22 Cooper & Hill, 1997). Contour values in metres. 10. Stratigraphy of the Otway Basin. Area covered in this report highlighted in red. 24 11. Simplified geological map of the Barrabool Hills showing the outcrop extent of the Barwon Hills 25 Member and Eumeralla Formation. Photomosaic interpretation below map is a view of the type section from the north side of the Barwon River. 12. Distribution of Sherbrook Group units and Late Cretaceous Eastern View Group in VIC/O-01(1), 26 VIC/O-01(2) and VIC/O-01(3). 13. Distribution of Wangerrip Group units and Early Tertiary Eastern View Group sediments in 28 VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3). 14. Outcrop – subcrop maturity (Rvmax%) map for the top of the Eumeralla Formation in the Eastern 36 Otway Basin. Otway Ranges data from Cooper et al. (1993) and Cooper (1995a). Areas of Mid-Cretaceous uplift and erosion overlain for comparison. 15. Source rock potential of the Eumeralla Formation in Stoneyford-1, Tirrengowa-1 and 37 Warracbarunah-2. PROSPECTIVITY OF EASTERN ONSHORE OTWAY BASIN 3 16. Burial history models for Location A in the Barwon Downs Graben (from Aburas & Boult, 2000). 39 Note slight increase in the maturity of the Eumeralla Formation during the Late Tertiary in Model 1. 17. Palynological map of the Eastern Otway Basin showing the outcrop – subcrop age of the 40 Eumeralla Formation. Areas of Mid-Cretaceous uplift and erosion overlain for comparison. From Constantine (2001). 18. Fractured basement and Pretty Hill Formation play fairway map. Prospective areas highlighted 42 in yellow. 19. Intra-Eumeralla Formation play fairway map. Prospective areas highlighted in yellow. 44 20. Base Tertiary play fairway map. Prospective areas highlighted in yellow. 46 List of Enclosures 1. Topography of VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 2. Well summary sheet: Anglesea-1 3. Well summary sheet: Hindhaugh Creek-1 4. Well summary sheet: Olangolah-1 5. Well summary sheet: Stoneyford-1 6. Well summary sheet: Tirrengowa-1 7. Well summary sheet: Nalangil-1 8. Well summary sheet: Ingleby-1 9. Well summary sheet: Warracbarunah-2 10. Well summary sheet: Irrewarra-1 11. Seismic coverage VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 12. SEGY coverage VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 13. Top Basement Time Structure Map, VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 14. Top Eumeralla Formation Time Structure Map, VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 15. Interpreted composite seismic sections 16. Bouguer gravity VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 17. Aeromagnetic coverage VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3): First Vertical Derivative (histogram equalised) 18. Land Use Map: VIC/O-01(1), VIC/O-01(2) and VIC/O-01(3) 4 PROSPECTIVITY OF EASTERN ONSHORE OTWAY BASIN Executive summary The three blocks on offer this year have been explored in the past by a number of companies who sunk a total of twenty one wells without encountering any significant hydrocarbon shows or accumulations. This In September 1998, a major fire at the Longford lack of success, however, is not considered a true processing plant in East Gippsland left Melbourne reflection of the prospectivity of the area because the with only two weeks emergency supply of gas. This majority of wells were sunk well before the first incident brought home the vulnerability of the gas seismic lines were acquired in 1960 and were not valid system due to its reliance on the Gippsland Basin, and structural tests. The first fourteen wells were spudded has led many petroleum exploration companies to between 1923 and 1948 (Anglesea-1, -2; Torquay-1, -2, re-evaluate the neighbouring Otway Basin which has -3, -4, -5, -6, -7; Geelong Oil Flow-1), followed by two long been thought to have little potential.