The second petroleum system in the Paleozoic rift is the Keyling, Hyland Bay-Permian. Source rocks include Lower Permian Keyling Formation delta-plain coals and marginal marine shales combined with Upper Permian Hyland Bay Formation prodelta shales. These source-rock intervals provide gas and condensate for fluvial, deltaic, and shallow marine sandstone reservoirs primarily within several members of the Hyland Bay Formation. The Keyling, Hyland Bay-Permian petroleum system is located in the Joseph Bonaparte Gulf, north of the Milligans-Carboniferous, Permian petroleum system, and may extend northwest under the Vulcan graben sub-basin.

The third and youngest petroleum system is the Jurassic, Early Cretaceous-Mesozoic system that is located seaward of Joseph Bonaparte Gulf on the Australian continental shelf, and trends southwest-northeast. Source-rock intervals in the Vulcan graben sub-basin include deltaic mudstones of the Middle Jurassic Plover Formation and organic-rich marine shales of the Upper Jurassic Vulcan Formation and Lower Cretaceous Echuca Shoals Formation. These intervals produce gas, oil, and condensate that accumulates in, shallow- to deep-marine sandstone reservoirs of the Challis and Vulcan Formations of Jurassic to Cretaceous age. Organic-rich, marginal marine claystones and coals of the Plover Formation (Lower to Upper Jurassic), combined with marine claystones of the Flamingo Group and Darwin Formation (Upper Jurassic to Lower Cretaceous) comprise the source rocks for the remaining area of the system. These claystones and coals source oil, gas, and condensate accumulations in reservoirs of continental to marine sandstones of the Plover Formation and Flamingo Group.

Shales of the regionally distributed Lower Cretaceous Bathurst Island Group and intraformational shales act as seals for hydrocarbons trapped in anticlines and fault blocks, which are the major traps of the province. 

Production in the Bonaparte Gulf Basin Province began in 1986 using floating production facilities, and had been limited to three offshore fields located in the Vulcan graben sub-basin. Cumulative production from these fields totaled more than 124 million barrels of oil before the facilities were removed after production fell substantially in 1995. Production began in 1998 from three offshore wells in the Zone of Cooperation through floating production facilities. After forty years of exploration, a new infrastructure of pipelines and facilities are planned to tap already discovered offshore reserves and to support additional development.

INTRODUCTION
There are two Total Petroleum Systems (TPS) located in a Devonian failed rift, that is now the site of the Joseph Bonaparte Gulf on the northern coast of Australia (Fig. 1). These systems consist of (1) a Carboniferous marine shale source rock with Carboniferous and Permian reservoir rocks, and (2) Permian shallow marine, coal, and deltaic shale source rocks with Permian reservoir rocks. The first (Milligans-Carboniferous, Permian, 391001) contains one assessment unit (Barnett, 39100101) for the purpose of estimating potential resources (Fig. 1). The second (Keyling, Hyland Bay-Permian, 391002) contains two assessment units (Petrel, 39100201, Vulcan, 39100202) (Fig. 1). The Petrel assessment unit is located in the Petrel sub-basin where gas discoveries have been made. The Vulcan assessment unit is located beneath the Mesozoic age petroleum system. 

A third petroleum system is located on the Australian continental shelf in a basin trend perpendicular to the Devonian rift, where maximum subsidence occurred in Jurassic through Cretaceous time. This system (Jurassic, Early Cretaceous-Mesozoic, 391003) consists of Jurassic and Cretaceous organic-rich marine shales and Jurassic and Cretaceous reservoirs in one assessment unit (Malita, 39100301) (Fig. 1).

Another petroleum system, consisting of Upper Devonian carbonates or Bonaparte Formation shales, may source shows in Upper Devonian Ningbing Limestone in combination with source shales of the Milligans Formation (McConachie and others, 1996). This possible petroleum system will not be discussed as part of this report.

Twenty nine fields have been identified in the Bonaparte Gulf Basin Province by Petroconsultants (1996) since exploration began in 1959, and only three have produced oil up to 1997(Australian Geological Survey Organisation, 1998). Known reserves for the province are estimated at 3.2 billion barrels of oil equivalent (BBOE) (Klett and others, 1997). In 1998, three new offshore fields on the Australian continental shelf began production (World Oil, 1999).