Release Area W16-22, Dampier Sub-basin, Northern Carnarvon Basin, Western Australia

HighlightsPrequalification for Release Area W16-17 closes on 20 October 2016, with the cash bidding auction to be held on 2 February 2017. Within one of Australia’s premier offshore producing basins Cash Bid Release Area overlies the Tusk and Oryx oil accumulations and is close

to numerous other oil and gas accumulations including Chamois, Corvus, Stag, Wandoo and Reindeer

Shallow water depths (40–50 m) Oil-prone Upper Jurassic and gas-prone Triassic to Middle Jurassic source rocks Stacked structural and stratigraphic targets at Triassic, Jurassic and Lower

Cretaceous levels Further guidance available, please refer to 2016 Special Notices

Release Area W16-22 is a small area, comprising two graticular blocks, that is considered mature in exploration terms and is available for cash bidding. The area intersects the Tusk and Oryx oil fields and is approximately 70 km northeast of Barrow Island and 70 km northwest of Dampier (Error: Reference source not found).

The Dampier Sub-basin is one of a series of large rift depocentres of the Northern Carnarvon Basin. The sub-basin is an elongate northeast-trending depocentre 170 km in length and 100 km in width, and contains Paleozoic to Cenozoic sedimentary successions 10-20 km in thickness (Error: Reference source not found). The main structural elements of the Dampier Sub-basin are aligned northeast-southwest: from northwest to southeast these are; the Kendrew Trough, Madeleine Trend, Lewis Trough, Legendre Trend and Enderby Terrace (Error: Reference source not found).

The Dampier Sub-basin hosts proven petroleum systems. Upper Triassic, Lower–Middle and Upper Jurassic source rocks have expelled hydrocarbons that are now reservoired in both structural and stratigraphic traps. Gas is predominantly sourced from Triassic to Middle Jurassic fluvio-deltaic sediments of the Mungaroo and Brigadier formations, the Murat Siltstone, and the Athol and Legendre formations. Oil is predominantly sourced from the Upper Jurassic Dingo Claystone. Structural trap styles in the sub-basin include tilted fault blocks, fault dependent rollovers, anticlines, drape features and horsts (Error: Reference source not found).

Figure 4 shows the existing data coverage of the Dampier Sub-basin. Although well coverage is not dense within the sub-basin, Brocket 1 and Oryx 1 wells lie within the Release Area and both have oil shows. The Release Area is also entirely covered by the Panaeus99ab 3D seismic survey. The release area is close to established infrastructure that could facilitate the development of discoveries (Error: Reference source not found).

Petroleum systems elements

Dampier Sub-basin

Sources Upper Jurassic marine Dingo Claystone (oil-prone) Lower–Middle Jurassic marine and deltaic Murat Siltstone and Athol and Legendre formations

(oil- and gas-prone) Triassic fluvio-deltaic Locker Shale and Mungaroo Formation (gas-prone)

Reservoirs M. australis Member and other sandstone units within the Lower Cretaceous marine to marginal marine Muderong Shale

Upper Jurassic turbiditic Angel Formation Middle–Upper Jurassic fluvio-deltaic to marine Legendre and Calypso formations Lower–Middle Jurassic marine to marginal marine Athol Formation Lower Jurassic fluvio-deltaic to marine North Rankin Formation Upper Triassic fluvio-deltaic to marine Brigadier Formation Middle–Upper Triassic fluvial to marginal marine Mungaroo Formation Lower Triassic marginal marine transgressive sand underlying the Locker Shale (unproven) Permian fluvio-deltaic to marine siliciclastic Kennedy Groups (unproven)

Seals Lower–Upper Cretaceous marine Gearle Siltstone Lower Cretaceous marine Muderong Shale (regional seal) and Forestier Claystone Upper Jurassic marine Dingo Claystone Lower–Middle Jurassic marine to marginal marine Athol Formation Lower Jurassic marine Murat Siltstone Lower Triassic Locker Shale (untested)

Traps Lower Cretaceous M. australis Member stratigraphic trap Lower Cretaceous low-side rollover structures and faulted horst blocks Upper Jurassic–Lower Cretaceous drape structures Upper Jurassic–Lower Cretaceous submarine fan stratigraphic traps Middle Jurassic faulted anticlines Upper Triassic–Lower Jurassic horst and tilted fault-blocks and associated drapes

Infrastructure and marketsRelease Area W16-22 overlies the Tusk and Oryx oil fields, is close to several other fields including the Stag and Wandoo developments, and is close to the Devil Creek and Pluto LNG Export pipelines. These pipelines connect producing offshore gas fields to onshore processing facilities and provide domestic gas to the Western Australian market and LNG to international markets.

Critical risksIn parts of the Dampier Sub-basin, trap integrity and reservoir preservation constitute significant exploration risks. Variable sandstone distribution/porosity within fine-grained deep-water sediments can also be problematic. Exploration risks associated with the inboard areas of the Dampier Sub-basin include hydrocarbon migration distance, biodegradation of oil in shallow reservoirs, and the potential absence of a competent seal. Late gas flushing of oil reservoirs is also considered to constitute an exploration risk in some areas..

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Marine and Environmental information

Release area W16-22 Release Area W16-22 is located 60 km from the Pilbara coastline to the south, and is 45 km from Enderby Island to

its southeast. W16-22 lies in shallow water depth (42-48 m) on the inner ramp of the continental shelf, overlying the Northern Carnarvon Basin.

Seabed sediment is dominated by relict biofragmental carbonate sediments (James et al, 2004) and it is gravelly sand in texture, mud content is minimal, with sediment dominated by shell fragments and other biogenic carbonate material (Colwell and von Stackelberg, 1981, Baker et al., 2008).

There is no detailed information on the shallow (< 100 m), subsurface geology .

Potential hazards may include tropical cyclones and shallow water for deep draught vessels.

Commonwealth Marine Reserves Release area W16-22 is directly adjacent to and on the eastern side of, Montebello Multiple Use Zone IUCN VI Commonwealth Marine Reserve.

Key Ecological FeaturesThere are three Key Ecological Features in the region including Release Area W16-22 (National Conservation Values Atlas, 2016). These are:

the Ancient coastline at 125 m depth (a unique seafloor feature that provides areas of enhanced biological productivity), located approximately 60 km to the north and northwest,

the Glomar Shoals, located approximately 72 km to the northeast, and

Continental Slope Demersal Fish Communities, located approximately 83 km to the northeast.

Biologically Important AreasRelease Area W16-22 intersects the following biologically important areas (National Conservation Values Atlas, 2016):

Includes the foraging area for vulnerable and migratory Whale Sharks.

Is within the foraging area, and adjacent to important nesting sites for Flatback, Green, Hawksbill and Loggerhead turtles.

Includes part of the migratory pathway of the protected Humpback Whale.

Overlaps foraging areas that are adjacent to important breeding areas for migratory seabirds such as the Fairy, Lesser Crested and Roseate Terns and Wedge-tailed Shearwater. Breeding for these species occurs throughout the year as indicated in the Table 1.

Jan Feb Mar Apr Mar Jun Jul Aug Sept Oct Nov Dec

Fairy Tern b b b

Lesser Crested Tern b b b b

Roseate Tern b b b

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Wedge-tailed Shearwater b b b b b b b b b b b

Table 1: Breeding periods (b) for key seabirds whose foraging areas overlap the Release Area.

Information ResourcesNational Conservation Values Atlas http://www.environment.gov.au/webgis-framework/apps/ncva/ncva.jsf

Gascoyne Commonwealth Marine Reserve http://www.environment.gov.au/topics/marine/marine-reserves/north-west/gascoyne

Montebello Commonwealth Marine Reserve http://www.environment.gov.au/topics/marine/marine-reserves/north-west/montebello

Western Australian Marine Parks and Reserves. https://www.dpaw.wa.gov.au/management/marine/marine-parks-and-reserves#

Commonwealth Fisheries http://www.afma.gov.au/fisheries/

Heritage https://www.environment.gov.au/topics/heritage

Geoscience Australia products

Regional geology and seismic Line Drawings of AGSO-Geoscience Australia’s Regional Seismic Profiles, Offshore Northern and Northwestern

Australia, Australian Geological Survey Organisation Record 2001/36 by Colwell and Kennard 2001.

1994 Barrow and Dampier Sub-basins Airborne Laser Fluorosensor (Mk III) Survey Interpretation Report. Australian Geological Survey Organisation Record 2001/16 by Cowley, 2001.

Barrow/Dampier, WA, 1993 (P597). Airborne Digital dataset by Richardson, 1993.

Survey 97: Operations Report for the Joint BMR/Woodside Petroleum High Resolution Seismic Program in the Dampier Sub-basin, October 1990. Bureau of Mineralogical Resources Record 1991/67 by O’Brien and Bickford, 1991.

Interpreted Horizons and Faults for Seismic Survey 101. Carnarvon Basin. Dataset by Kennard et al, 2003.

Interpreted Horizons and Faults for Seismic Survey 110. Carnarvon Basin. Dataset by Kennard et al, 2003.

Carnarvon Cretaceous-Tertiary Tie Report. Australian Geological Survey Organisation Record 1996/36 by Romine and Durrant, 1996.

Stratigraphy Northern Carnarvon Basin Biozonation and Stratigraphy Chart 36. Chart by Kelman et al, 2013.

Petroleum systems and accumulations Source Rock Time-slice Maps: Offshore Northwest Australia, 2004. Dataset by West et al, 2004.

Australian Petroleum Systems: Dampier Sub-basin Module. Australian Geological Survey Organisation Record 1993/31 by Spencer et al, 1993.

The Oils of Western Australia II. Report by Edwards and Zumberge, 2005.

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Australian Petroleum Accumulations Report, Carnarvon Basin, Western Australia. Australian Geological Survey Organisation Report by Felton et al, 1993.

Characterisation of Natural Gases from West Australian Basins. AGSO and Geotechnical Services Non-Exclusive Study, 2000.

Light Hydrocarbon Geochemistry of the WA-28-P Area, Dampier Sub-basin, Western Australia: Rig Seismic Survey 97: Project 121.19. Bureau of Mineral Resources Record1992/61 by O’Brien, 1992.

Search for these and other Geoscience Australia reports and products at www.ga.gov.au/search

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Key referencesADAMSON, K.R., LANG, S.G., MARSHALL, N.G., SEGGIE, R.J., ADAMSON, N.J. AND BANN, K.L., 2013—Understanding the Late Triassic Mungaroo and Brigadier deltas of the Northern Carnarvon Basin, North West Shelf, Australia. In: Keep, M. and Moss, S.J. (eds), 2013, The Sedimentary Basins of Western Australia IV: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2013, 29 pp.

AMPOL EXPLORATION LIMITED, 1992—Wandoo-1 Well Completion Report. Ampol Exploration Limited (unpublished).

ANDERSON, P.F., BINGAMAN, P., GRAVES, K., FERNANDES, F., O’SULLIVAN, F. AND BETTS, S., 2012—Recent production and drilling success of the Stag oil field from multidisciplinary evaluation of OBC seismic data. Leading Edge, (Special Section) Marine and Seabed Technology, 31(4), 387–391.

APACHE ENERGY, 2005—Reindeer-1 WA-209-P Well Completion Report, Interpretive Data. Apache Energy (unpublished).

APACHE ENERGY, 2008— Brocket-1 WA-209-P Well Completion Report, Interpretive Data. Apache Energy (unpublished).

AUSTRALIAN OCCIDENTAL PTY LTD, 1983—Arabella-1 Well Completion Report, WA-192-P. Australian Occidental Pty Ltd (unpublished).

BAKER, C., POTTER, A., TRAN, M. AND HEAP, A.D., 2008—Sedimentology and geomorphology of the northwest marine region: a spatial analysis. GeoScience Australia Record, 2008/07, 220.

BALLESTEROS, M., 1998—Recent discoveries in the Barrow and Dampier sub-basins: Agincourt, Alkimos, Wonnich, Reindeer and Legendre fields. In: Purcell, P.G. and R.R. (eds), 1998, The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 1998. 541–552.

BARBER, P., 2013—Oil exploration potential in the Greater Northern Australian – New Guinea Super Gas Province. In: Keep, M. and Moss, S.J. (eds), 2013, The Sedimentary Basins of Western Australia IV: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2013, 32 pp.

BISHOP, M.G., 1999—Total petroleum systems of the Northwest Shelf, Australia: the Dingo-Mungaroo/Barrow and Locker-Mungaroo/Barrow. U.S. Department of the Interior, U.S. Geological Survey, Open File Report 99-50-E, http://greenwood.cr.usgs.gov/energy/WorldEnergy/OF99-50E/ (last accessed 18 December 2014).

CATHRO, D.L. AND KARNER, G.D., 2006—Cretaceous–Tertiary inversion history of the Dampier Sub-basin, northwest Australia: insights from quantitative basin modelling. Marine and Petroleum Geology, 23, 503–526.

COLWELL, J.B. AND VON STACKELBERG, U., 1981—Sedimentological studies of Cainozoic sediments from the Exmouth and Wallaby Plateaus, off northwest Australia. BMR J. Aust. Geol. Geophysics, 6, 43-50.

CROWLEY, A.J. AND COLLINS, E.S., 1996—The Stag Oilfield. The APPEA Journal, 36(1), 130–141.

DYSON, I.A., 1998—Stratigraphy and sedimentology of the M. australis Sandstone, Barrow and Dampier sub-basins. In: Purcell, P.G. and R.R. (eds), 1998, The Sedimentary Basins of Western Australia 2: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 1998. 503–514.

GRADSTEIN, F.M., OGG, J.G. SCHMITZ, M.D. AND OGG, G.M. (eds), 2012—The Geologic Time Scale 2012; Volumes 1 and 2. Elsevier BV, 1144 pp.

HILL, G., 1994—The role of the pre-rift structure in the architecture of the Dampier Basin area, North West Shelf, Australia. The APEA Journal, 34, 602–613.

HOCKING, R.M., 1990—Carnarvon Basin. In: Geology and Mineral Resources of Western Australia. Western Australia Geological Survey, Memoir 3, 347–495.

JAMES, N.P., BONE, Y., KYSER, T.K., DIX, G.R. AND COLLINS, L.B., 2004—The importance of changing oceanography in controlling late Quaternary carbonate sedimentation on a high-energy, tropical, oceanic ramp: north-western Australia. Sedimentology, 51, 1179-1205.

KELMAN, A.P., NICOLL R.S., KENNARD, J.M., MORY, A.J., MANTLE, D.J., LE POIDEVIN, S., BERNARDEL, G., ROLLET, N. AND EDWARDS, D., 2013—Northern Carnarvon Basin, Biozonation and Stratigraphy, Chart 36, Geoscience Australia.

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KOPSEN, E. AND MCGANN, G., 1985—A review of the hydrocarbon habitat of the eastern and central Barrow–Dampier sub-basin, Western Australia. The APEA Journal, 25(1), 154–176.

LONGLEY, I.M., BUESSENSCHUETT, C., CLYDSDALE, L., CUBITT, C.J., DAVIS, R.C., JOHNSON, M.K., MARSHALL, N.M., MURRAY, A.P., SOMERVILLE, R., SPRY, T.B. AND THOMPSON, N.B., 2002—The North West Shelf of Australia – a Woodside perspective. In: Keep, M. and Moss, S.J. (eds), 2002, The Sedimentary Basins of Western Australia 3: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2002. 27–88.

MARSHALL, N.G. AND LANG, S.C., 2013—A new sequence stratigraphic framework for the North West Shelf, Australia. In: Keep, M. and Moss, S.J. (eds), 2013, The Sedimentary Basins of Western Australia IV: Proceedings of the Petroleum Exploration Society of Australia Symposium, Perth, WA, 2013, 32 pp.

MILLER, L.R. AND SMITH, S.A., 1996—The development and regional significance of rift-related depositional systems in the Dampier Sub-basin. The APPEA Journal, 36(1), 369–384.

O’BRIEN, G.W., COWLEY, R., LAWRENCE, G., WILLIAMS, A.K., WEBSTER, M., TINGATE, P. AND BURNS, S., 2003—Migration, leakage and seepage characteristics of the offshore Canning Basin and Northern Carnarvon Basin: Implications for hydrocarbon prospectivity. APPEA Journal, 43, 149–166.

ROMINE, K.K., DURRANT, J.M., CATHRO, D.L. AND BERNARDEL, G., 1997—Petroleum play element prediction of the Cretaceous–Tertiary basin phase, Northern Carnarvon Basin. The APPEA Journal, 37(1), 325–339.

SMITH, T. E., OGG, J., KELMAN, A., ABBOTT, S. AND BERNECKER, T., 2015—Towards common stratigraphic frameworks for Australia’s offshore hydrocarbon provinces. The APPEA Journal. 55(1), 105–111.

STUUT, J.-B.W., TEMMESFELD, F. AND DE DECKKER, P., 2014—A 550 ka record of aeolian activity near North West Cape, Australia: inferences from grain-size distributions and bulk chemistry of SE Indian Ocean deep-sea sediments. Quaternary Science Reviews, 83, 83-94.

TAO, C., BAI, G., LIU, J., DENG, C., LU, X., LIU, H. AND WANG, D., 2013—Mesozoic lithofacies, palaeogeography and petroleum prospectivity in North Carnarvon Basin, Australia. Journal of Palaeogeography, 2(1), 81–92.

THOMAS, G.P., LENNANE, M.R., GLASS, F., WALKER, T., PARTINGTON, M., LEISCHNER, K.R. AND DAVIS, R.C., 2004—Breathing new life into the eastern Dampier Sub-basin: an integrated review based on geophysical, stratigraphic and basin modelling evaluation. The APPEA Journal, 34(1), 123–147.

WOODSIDE OFFSHORE PETROLEUM PTY LTD, 1996—Saffron-1 Well Completion Report, Volume 2 (Interpretive), WA-1-P, Dampier Sub-basin. Woodside Offshore Petroleum Pty Ltd (unpublished).

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