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Yampi Shelf

Bids close 29 October 2015

  • Underexplored area adjacent to a proven Mesozoic oil and gas province
  • Adjacent to the Cornea oil accumulation
  • Close to Ichthys Gas Pipeline to Bladin Point, Darwin (currently under construction)
  • Shallow water depths (<70–100 m)
  • Combined structural and stratigraphic traps, including Cretaceous drape over erosional basement highs
  • Special Notices apply, refer to Guidance Notes.

Release Area W15-18 is located on the Yampi Shelf, on the southeastern side of the Cornea oil accumulation (Figure 1). It consists of 37 graticular blocks, approximately 70 to 150 km off Western Australia, in water depths from less than 70 m to 100 m. The Yampi Shelf marks the southeastern edge of the Browse Basin, and is characterised by shallow, gently basinward-dipping to relatively flat-lying basement. This basement is typically highly eroded with a distinct, rugose palaeotopographic relief and is onlapped by Permian to Mesozoic and Cenozoic sediments that progressively thin across the terrace and shelf from about 5 km to less than 500 m thick. The Ichthys Pipeline, currently under construction and due for completion in 2016, passes within 5 km of the Release Area.

Numerous petroleum systems have been proven within the nearby Caswell Sub-basin and the Cornea accumulation on the Yampi Shelf hosts oil and gas in an Albian sandstone reservoir. Organic-rich rocks with fair to moderate oil potential occur within the Plover, Vulcan and Echuca Shoals formations (Figure 2). Gas-prone, high-quality coals and pro-delta shales occur within the Plover Formation. Stratigraphic traps include Cretaceous drape over erosional, fractured basement highs on the Yampi Shelf (Figure 3). Figure 4 shows the existing data coverage of the region, with relatively few wells but comprehensive 2D seismic coverage, plus the Cornea 3D seismic survey covering part of the Release Area.

Petroleum systems elements

Yampi Shelf

Sources
  • Aptian–Cenomanian shallow marine lower and upper Jamieson Formation (oil-prone,
     immature–marginally mature)
  • Valanginian–Aptian marine Echuca Shoals Formation (oil-prone)
  • Callovian–Valanginian marine Vulcan Formation (oil-prone)
  • Lower–Middle Jurassic fluvio-deltaic Plover Formation (oil- and gas-prone)
Reservoirs
  • Albian lower to upper shoreface marine Heywood Formation
  • Lower Cretaceous Echuca Shoals Formation (shallow marine sandstones)
Seals

Regional Seals

  • Lower Cretaceous marine Echuca Shoals Formations

Intra-formational Seals

  • Cretaceous marine claystones of the Heywood Formation
Traps
  • Cretaceous drape onto erosional fractured basement highs and stratigraphic pinch-out traps

Infrastructure and markets

Four separate projects are in various stages of development in the Browse Basin: the Prelude (WA‑44‑L) FLNG Project (encompassing the Prelude and Concerto accumulations), the Ichthys (WA‑50‑L) LNG Project, the proposed Browse FLNG Development, encompassing the Torosa (WA‑30‑R), Brecknock (WA-29-R and WA‑32‑R) and Calliance (WA‑28‑R, WA‑31‑R) accumulations, and the proposed Crux (AC/RL9) gas and liquids project. The Ichthys gas pipeline to Bladin Point, Darwin is currently under construction, with the Ichthys development due for completion in 2016.

Critical risks

The quality of the shallow reservoir sandstones at Cornea has proved to be poor, with poor well test results being compounded by the biodegraded nature of the oil. The oil column has also been reduced by subsequent gas charge and possible tilting, flushing the remainder of the accumulation. It is likely that the discoveries at Focus 1 and Sparkle 1 represent hydrocarbons spilt from the Cornea structure. These discoveries provide evidence that oil and gas sourced from multiple formations within the Caswell Sub-basin can migrate over long distances onto the adjacent shelf. The plays within the area are dependent on locating good quality reservoir with sufficient seal that have access to adequate hydrocarbon charge.

Data sets

Wells Data and Seismic Survey listings for the Yampi Shelf are available on the Supporting Information page.

Geoscience Australia products

Regional geology and seismic

Stratigraphy

Petroleum systems and accumulations

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AGSO BROWSE BASIN PROJECT TEAM, 1997—Browse Basin High Resolution Study, Interpretation Report, North West Shelf, Australia. Australian Geological Survey Organisation Record 1997/38.

BENSON, J.M., BREALEY, S.J., LUXTON, C.W., WALSHE, P.F. AND TUPPER, N.P., 2004—Late Cretaceous ponded turbidite systems: a new stratigraphic play fairway in the Browse Basin. The APPEA Journal, 44(1), 269–285.

BLEVIN, J.E., BOREHAM, C.J., SUMMONS, R.E., STRUCKMEYER, H.I.M. AND LOUTIT, T.S., 1998—An effective Lower Cretaceous petroleum system on the North West Shelf: evidence from the Browse Basin. 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, 397–420.

BLEVIN, J.E., STRUCKMEYER, H.I.M., CATHRO, D.L., TOTTERDELL, J.M., BOREHAM, C.J., ROMINE, K.K., LOUTIT, T.S. AND SAYERS, J., 1998—Tectonostratigraphic framework and petroleum systems of the Browse Basin, North West Shelf. 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, 369–395.

BRINCAT, M.P., LISK, M., KENNARD, J.M., BAILEY, W.R. AND EADINGTON, P.J., 2004—Evaluating the oil potential of the Caswell Sub-basin; insights from fluid inclusion studies. Special Publication - Northern Territory Geological Survey, 437–455.

INGRAM, G.M., EATON S. AND REGTIEN, J.M.M., 2000—Cornea case study—lessons for the future. The APPEA Journal, 40 (1), 56–65.

KELMAN, A.P., KENNARD, J.M., NICOLL, R.S., LAURIE, J.R., EDWARDS, D.S., KHIDER, K AND LE POIDEVIN, S., 2014—Browse Basin Biozonation and Stratigraphy 2014 Chart 32. Geoscience Australia Biozonation and Stratigraphy Chart Series (http://www.ga.gov.au/corporate_data/76687/Chart_32_Browse_Basin_2014.pdf).

KENNARD, J.M., DEIGHTON, I., RYAN, D., EDWARDS, D.S. AND BOREHAM, C.J., 2004—Subsidence and thermal history modelling: new insights into hydrocarbon expulsion from multiple petroleum systems in the Browse Basin. In: Ellis, G.K., Baillie, P.W. and Munson, T.J. (eds), Timor Sea Petroleum Geoscience. Proceedings of the Timor Sea Symposium, Darwin, 19–20 June 2003. Northern Territory Geological Survey, Special Publication 1, 411–435.

LAWRENCE, S.H.F., THOMPSON, M., RANKIN, A.P.C., ALEXANDER, J.C., BISHOP, D.J. AND BOTERHOVEN, B., 2014—A new structural analysis of the Browse Basin, Australian North West Margin. The APPEA Journal 54, 1–10.

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.

PRYER, l., BLEVIN, J., NELSON, G., SANCHEZ, G., LEE, J-D, CATHRO, D, GRAHAM, R. AND HORN, B., 2014—Structural architecture and basin evaluation of the North West Shelf. The APPEA Journal 54 (extended abstract).

RADLINSKI, A.P., KENNARD, J.M., EDWARDS, D.S., HINDE, A.L. AND DAVENPORT, R., 2004—Hydrocarbon generation and expulsion from Early Cretaceous source rocks in the Browse Basin, North West Shelf, Australia: a small angle neutron scattering study. The APPEA Journal, 44(1), 151–180.

ROLLET, N., LOGAN, G.A., KENNARD, J.M., O’BRIEN, P.E., JONES, A.T. AND SEXTON, M. 2006—Characterisation and correlation of active hydrocarbon seepage using geophysical data sets; an example from the tropical, carbonate Yampi Shelf, Northwest Australia. Marine and Petroleum Geology, 23(2), 145–164.

STRUCKMEYER, H.I.M., BLEVIN, J.E., SAYERS, J., TOTTERDELL, J.M., BAXTER, K. AND CATHRO, D.L., 1998—Structural evolution of the Browse Basin, North West Shelf: new concepts from deep-seismic data. 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, 345–367.

SYMONDS, P.A., COLLINS, C.D.N. AND BRADSHAW, J., 1994—Deep structure of the Browse Basin: implications for basin development and petroleum exploration. In: Purcell, P.G. and R.R. (eds), The Sedimentary Basins of Western Australia: Proceedings of Petroleum Exploration Society of Australia Symposium, Perth, 1994, 315–331.

VOLK, H., BRINCAT, M.P., GEORGE, S.C., KENNARD, J. M., EDWARDS, D.S., BOREHAM, C.J., AHMED, M. AND LISK, M. 2005—Clues to fill histories of gas fields in the Caswell Sub-basin; evidence from the distribution and geochemistry of palaeo-oils. The APPEA Journal, 45(1), 679.

WILLIS, I., 1988—Results of exploration, Browse Basin, North West Shelf, Western Australia. In: Purcell, P.G. and R.R. (eds), The North West Shelf, Australia: Proceedings of Petroleum Exploration Society of Australia Symposium, Perth, 1988, 259–272.

Figures

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Figure 1

 Browse Basin-Yampi Shelf-figure-1 map image
Structural elements of the Yampi Shelf in the vicinity of the 2015 Release Area, showing petroleum fields and discoveries, the location of the regional seismic section (Figure 3), and the 2015 and 2014 Release Areas. 2015 Release Areas shown in outline only are discussed elsewhere.
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Figure 2

 Browse Basin-Yampi Shelf-figure-2 map image
Stratigraphy and hydrocarbon discoveries on the Yampi Shelf, based on the Browse Basin Biozonation and Stratigraphy Chart 32 (Kelman et al, 2014). Geologic Time Scale after Gradstein et al (2012).
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Figure 3

 Browse Basin-Yampi Shelf-figure-3 map image
Seismic line s119/04 across the Caswell Sub-basin and Yampi Shelf. Interpretation by Geoscience Australia. Location of the seismic line is shown in Figure 1.
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Figure 4

 Browse Basin-Yampi Shelf-figure-4 map image
Seismic and well data in the vicinity of the Release Area on the Yampi Shelf, Browse Basin. 2015 Release Areas shown in outline only are discussed elsewhere.
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