Abstract

The Browse Basin lies offshore from the remote Western Australia Kimberley region and hosts vast reserves of gas, some of which are rich in condensate, making it Australia's next major conventional liquefied natural gas (LNG) province on the North West Shelf. The super-giant Ichthys gas accumulation is estimated to host 12.8 trillion cubic feet (Tcf) of gas and 527 million barrels (mmbbl) of condensate (CGR = 60 bbl/MMscf) making it the largest hydrocarbon accumulation with recoverable liquids found in Australia since the discovery of the Gippsland Basin and Barrow Island oil fields in the 1960s. Similar amounts of gas, albeit drier (CGR = 20-30 bbl/MMscf) are hosted within the super-giant Brecknock, Calliance and Torosa accumulations (15.9 Tcf gas, 436 mmbbl condensate). Despite the extensive ongoing exploration activity and prior research interest [1, 2, 3 and 4], the basin's petroleum systems have not been updated for a decade. Collating the existing molecular and isotopic datasets for the wet gases and associated hydrocarbon liquids, along with the biomarker and 13C/12C and D/H ratios of the n-alkanes for the crude oils, has enabled the origin and extent of the petroleum systems to be redefined. In doing so, it is apparent that the filling of the gas accumulations within the Caswell Sub-basin and along the Scott Reef-Brecknock trend is complex, with the component gases originating from multiple organic and inorganic sources. Differing extents of biodegradation and recharge are observed in the Cornea and Gwydion oil and gas accumulations on the Yampi Shelf. Four petroleum systems (PS) are defined, as illustrated in Figure 1 by their 13C n-alkane isotopic profiles. - The Plover-Plover PS is a basin-wide gas-prone system where the gas is reservoired within the Early-Middle Jurassic Plover Formation (e.g. Brecknock-Torosa, Ichthys) and sourced from mixed terrestrial and marine organic matter deposited in fluvio-deltaic sediments; - The Plover/Vulcan-Vulcan PS occurs within the central Caswell Sub-basin at Ichthys and Prelude/Concerto and is a wet gas-prone system reservoired within the Brewster Member, upper Vulcan Formation, which has a more marine source affinity with the additional hydrocarbons probably being sourced from the lower Vulcan Formation. - The Plover/Vulcan-Nome PS is a gas-prone system within the Heywood Graben where the Nome Formation reservoir at Crux is sourced from mixed terrestrial and marine organic matter deposited within Jurassic sediments. - The Echuca Shoals-Heywood PS is an oil- and gas-prone system on the Yampi Shelf (Cornea and Gwydion) sourced by marine algae and bacterial organic matter within Lower Cretaceous sediments [2]. The oils and gases vary in their degree of biodegradation. Further work is in progress to correlate the wet gases and oils with their source rocks.
Google map showing geographic bounding box with values North bound -12.0 East bound 130.0 West bound 120.0 South bound -20.0

Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2014-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

82083 Product http://www.ga.gov.au/metadata-gateway/metadata/record/82083/

Keywords

GA Publication
geochemistry
geology
WA
Geology

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-12.0
East bound
130.0
West bound
120.0
South bound
-20.0

TEMPORAL EXTENT

2014-11-01 / 2014-12-03

Lineage

RD abstract for Australian Organic Geochemistry (AOGC) conference

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Source Description

Browse Basin geochemistry data generated by GA laboratories
Biomarker and isotopic dataset

Metadata File Identifier

01f6feb9-f681-1253-e054-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
custodian
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address