22-1/H54-7/3

60% coverage to south 22-1/E52-10/2 Contour interval: 20

22-1/H51-15/10 Vertical scale: 10

22-1/I55-5/8 Vertical scale: 25

22-2/F53-3/4 Vertical scale: 500

22-2/F53-3/1 Contour interval: 10

22-1/I51-3/2 Contour interval: 20

22-1/I54-16/1 Contour interval: 10

22-1/I51-3/7 Vertical scale: 100

Available geological and geophysical data for the dominantly Devonian Darling Basin of western New South Wales indicate a high risk for petroleum exploration. Hydrocarbon prospectivity is confined to the concealed western Darling Basin, where block-faulted, graben-like troughs contain a generally thick sequence of Middle Devonian to Lower Carboniferous continental sediments, underlain by Lower Devonian marine sediments. Geochemical data for cores from BMR Ivanhoe No. 1 and from thirteen petroleum exploration wells held on open file at BMR are used to evaluate source rock potential and organic maturation levels. The continental sediments have no source potential. The marine Lower Devonian Amphitheatre Formation has a generally low organic carbon content, is thought to be gas prone, and is thermally mature to overmature for oil generation. The geochemical data support the hypothesis that trough flanks and margins, where sediments have not been too deeply buried or thermally altered, offer the best prospects for preservation of source and reservoir rocks. On the basis of the limited data available, the eastern flank of the Lake Wintlow High - Wilcannia High is considered the most prospective region of the Darling Basin.