The Darling Basin occupies approximately 100,000 km2 of western New South Wales, ringed in the north by the towns of Broken Hill, Wilcannia and Cobar and stretching southward to near the Murray River.
The Darling Basin is a Late Silurian to Early Carboniferous sedimentary basin within the Tasman Fold Belt System of eastern Australia. It overlies basement disjunctions coinciding with boundaries between the Kanmantoo, Lachlan and southern Thomson Fold Belts. The bulk of strata are Devonian with a known thickness of up to 8,000 metres. They largely comprise continental red-bed facies but probably include marginal marine facies in the latest Silurian and the Early Devonian. Most of the basin is veneered by Murray Basin Cainozoic sediments. Seismic sequence analysis has identified an orogenic event/unconformity associated with the Tabberabberan Orogeny (~Emsian) and a prominent basin structuring/termination event associated with the Kanimblan/Alice Springs Orogeny (Middle Carboniferous).
The Darling Basin has been only sparsely explored with most wells sited on poorly-defined structures. Exploration drilling commenced in 1963 and has continued sporadically with about a dozen wells having been located largely in the western part of the Basin. Indications of the possible presence of petroleum include gas of unknown origin seeping from water bores, potential source rocks in sparsely sampled Early Devonian and a few "shows" reported from wells. Reservoir units have good porosity and permeability. Cambrian to Ordovician carbonates and shales, where present beneath the basin, could also be potential source rocks
The Moomba to Sydney pipeline crosses the basin, making it an attractive place to find gas for the burgeoning eastern seaboard market.