The Otway Basin is a broadly northwest to southeast striking rift basin that extends for approximately 500 km along the onshore and offshore parts of southeastern Australia (Figure 1). Approximately 80% of the basin is located offshore and 20% onshore. In total, the basin covers an area of approximately 155 000 km2; 45% of the basin is located in Victoria, 35% in South Australia and the remaining 20% within Tasmanian jurisdiction.
The Otway Basin is an important gas-producing region with discoveries onshore and in shallow water areas offshore approximately 170–220 km west-southwest of Melbourne, the State Capital of Victoria, delivering gas to the southeastern Australian energy market (Figure 2). Natural gas from Victoria, transported via the Port Campbell−Adelaide pipeline and the South East South Australia Pipeline, powers the 80 MW Ladbroke Grove power station adjacent to the Katnook facility. This gas also supplies markets serviced by the South East Pipeline System, replacing declining supply from the local onshore fields (Figure 3). The greater Melbourne region represents a large domestic gas market and is supported by two major petroleum refineries in Geelong and Altona. Portland, on the western Victorian coast, is a deep-water port suited to offshore operations and is serviced by an excellent road and rail network.