The Gippsland Basin Province 3930, located on the southeastern coast of Australia, is formed from two successive failed rifts that developed into a passive margin during the Cretaceous. Formation of this basin is related to the break up of Gondwana, which resulted in the separation of Antarctica from Australia, and the separation of the New Zealand and Lord Howe Rise continental crust from Australia. Coals and coaly shales of Late Cretaceous through Eocene age are the source rocks for oil and gas that accumulated predominantly in anticlinal traps. The basin was Australia’s major producing basin until 1996 when daily oil/condensate production from the North West Shelf surpassed it.
 

INTRODUCTION
One Total Petroleum System (TPS), Latrobe 393001, is described in the Gippsland Basin Province with one assessment unit, Gippsland 39300101 (Fig. 1). It consists of Upper Cretaceous upper coastal plain coals and coaly shales of the Latrobe Group as the source rock and Upper Cretaceous through Eocene Latrobe Group fluvial, deltaic, and marginal marine sandstones as reservoir rocks (Fig. 2). The available data indicate that the discovered reserves in the Gippsland Basin are derived from these terrestrial coals and coaly shales (Bradshaw and others, 1998; Rahmanian and others, 1990; Howes, 1997; Fielding, 1992; MacGregor, 1994; Hocking, 1976). Nearly three quarters of the estimated discovered recoverable oil and gas reserves are found in anticlines, domes, and rollover traps (Petroconsultants, 1996). Almost 85% of the volume of reserves is in reservoir sandstones of the Latrobe Group (Petroconsultants, 1996).

The underlying and adjacent Strzelecki (Lower Cretaceous) and Golden Beach (Lower and Upper Cretaceous, also known as the lower Latrobe) Groups (Fig. 2) may have contributed hydrocarbons to overlying accumulations and adjacent accumulations where vertical and lateral out-of-basin migration paths are considered. Recent work describing the source-rock potential, reservoir quality, and trap preservation of Strzelecki and Golden Beach strata includes Mehin and Bock (1998) and Partridge (1996). These strata will be described here, although, not developed into petroleum systems at this time.

The Gippsland Basin has been a significant source of oil and gas in Australia since offshore production began there in 1969. Reserve estimates published by McPhee (1976) listed estimated recoverable reserves of 1,972 million barrels oil (MMBO), 174 million barrels condensate (MMBCond), 469 million barrels liquid petroleum gas (MMBLPG), and 222 billion cubic meters gas (Bm3) (7,840 billion cubic feet gas (BCFG)). It is interesting to note that since offshore production began in 1969 the Gippsland Basin has produced 3,446.5 MMBO and 4,779.5 BCFG with remaining reserves totaling 629.9 MMBO and 4,827.8 BCFG (Mehin and Bock, 1998). Revived exploration efforts for and renewed exploitation of gas reserves to serve growing markets in New South Wales, Victoria, and Tasmania would be facilitated by the planned new gas pipeline from Victoria to Sydney in New South Wales (Hart’s E & P, 1999).