Ann: Major Milestone for Cliff Head Oil Export, page-64

Of the 20 commercial hydrocarbon fields discovered in the northern Perth Basin, Dongara is by far the largest, with 14.3 Gm3 (508 Bcf) of original in-place gas and 16.6 GL (104 MMbbl) of original in-place oil.
Additional discoveries were made both in the northern and southern Perth Basin, some of which are currently being delineated.Petroleum-system analysis of the basin indicates that mature source rocks are widespread, reservoirs are abundant, and structures are well timed for hydrocarbon entrapment. These petroleum systems are defined as Transitional and Gondwanan.
The seal is considered to be a critical factor owing to the intense faulting and high sand-to-shale ratio of the post-Lower Triassic succession.The main source for gas is the Permian Irwin River Coal Measures, with reservoirs in the Upper Permian and Jurassic.
The main source for oil is the base of the marine Lower Triassic Kockatea Shale, with reservoirs in Lower Triassic and Permian sandstones. Oil was also recovered from the Lower Cretaceous reservoir immediately offshore from Perth at Gage Roads 1. Before 2001, the success rate of wells drilled in the northern part of the basin was about one in ten. Since then, several discoveries in 2001 and the application of 3D seismic surveys led to a higher success rate. Major play types include Permian–Triassic and Jurassic anticlines, as well as Permian-Triassic tilted fault blocks and stratigraphic traps.”




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