A large part of the onshore NT comprises oil and gas bearing sedimentary basins including the Amadeus, Ngalia, Pedirka, Simpson, Eromanga, Georgina and greater McArthur basins.
The only currently producing onshore basin in the Northern Territory is the Amadeus Basin, where gas production commenced from Palm Valley in 1983 and oil and gas production from Mereenie commenced in the following year. Up to five conventional petroleum systems are present in the Amadeus Basin, including the Ordovician system that hosts the Mereenie and Palm Valley fields. Three of the other four petroleum systems are Neoproterozoic in age and the fourth is Neoproterozoic to Cambrian. A variety of structural and stratigraphic traps are present within the basin. Recent developments by Central Petroleum Ltd in the Amadeus Basin include the development of the Surprise oil field in 2014, and the commencement of gas production from the Dingo field In December 2015. The Amadeus Basin also has considerable unconventional petroleum potential, including shale gas and oil in the Horn Valley Siltstone, and tight gas in the Pacoota and Stairway sandstones.
The Palaeo-Mesoproterozoic McArthur Basin (including the Beetaloo Sub-basin) has long been recognised as having potential for petroleum, and both oil and gas are known to have flowed from petroleum wells and mineral exploration drillholes. The McArthur and Roper groups are recognised as having the most petroleum potential. The McArthur Basin is now recognised as a substantial shale gas play, likely to contain hundreds of Tcf of prospective resources in place, particularly in the Beetaloo Sub-basin, which is a depocentre of Mesoproterozoic Roper Group sediments that occurs between Mataranka and Elliot. Origin Energy, Pangaea Resources and Santos all drilled wells targeting shale gas in the Beetaloo Sub-basin in 2014 and 2015, with published results suggesting thick columns of gas associated with the prospective middle Velkerri Formation shale. The other main shale formation of interest in the McArthur Basin is the 1640 Ma Barney Creek Formation in the McArthur Group, which is the source rock for gas discoveries by Armour Energy Ltd in the basin.
In the southern Georgina Basin, the middle Cambrian succession contains potentially prolific marine source rocks particularly in the Thorntonia Limestone and lower Arthur Creek Formation Numerous conventional stratigraphic and structural traps are present within the basin, which also has considerable unconventional shale gas and oil potential in the lower Arthur Creek Formation, and shale gas potential in the upper Arthur Creek Formation. The Wiso Basin is virtually unexplored for petroleum and the most prospective area, the Lander Trough, has not been drill tested.
The onshore Bonaparte Basin is the extension of a producing offshore basin, and has potential for both conventional and unconventional gas and oil.
The Pedirka and Eromanga basins have an abundance of organically rich source rocks, porous and permeable reservoirs with effective vertical seals, and closed anticlinal structures. The Pedirka Basin, includes direct correlatives of the Cooper Basin in South Australia and Queensland.