In lithostratigraphic terms, the basin fill of the Otway Basin is divided into five major sedimentary successions: The Otway Supergroup and the Sherbrook, Wangerrip, Nirranda and Heytesbury groups. In a recent, regional basin analysis study of the entire Otway Basin, Geoscience Australia authors have proposed a new sequence stratigraphic framework for the Otway Basin (Krassay et al. 2004). In the new tectonostratigraphic framework, seven major basin phases and their eight component supersequences (2^ndorder sequences) are recognised as follows;

1. Tithonian?-Barremian rifting that resulted in the deposition of thick continental and fluvio-lacustrine sediments of the Crayfish Supersequence,
2. Aptian-Albian post-rift, volcaniclastic, fluvio-lacustrine deposition of the Eumeralla Supersequence,
3. mid-Cretaceous compression and inversion,
4. Late Cretaceous rifting and associated coastal-plain, deltaic and marine deposition of the Shipwreck and Sherbrook Supersequences,
5. latest Maastrichtian to Middle Eocene basin reorganisation and early thermal subsidence of the Wangerrip Supersequence (coastal plain, deltaic and shallow marine deposition),
6. local inversion and thermal subsidence of the Nirranda Supersequence (Middle Eocene to Early Oligocene near-shore to offshore, mixed clastic and carbonate deposition) followed by thermal subsidence and progressive compression of the Heytesbury Supersequence (Late Oligocene to Late Miocene, progradational open-marine carbonate deposition) leading to Late Miocene uplift and erosion, and,
7. Plio-Pleistocene deposition of the Whalers Bluff Supersequence (mixed siliciclastic-carbonate succession).

Stratigraphic and Basin Event Chart of the Otway Basin

The main exploration targets in the Otway Basin are the Waarre Sandstone at the base of the Sherbrook Group (Shipwreck Supersequence), and sandstones of the Pretty Hill Formation (Crayfish Supersequence) and Katnook Sandstone/Windermere Sandstone Member in the Early Cretaceous section. The main source rocks are coals and coaly shales of the Aptian to Albian aged Eumeralla Formation (Eumeralla Supersequence). Regional and intraformational seals exist in the Pretty Hill, Laira, Eumeralla and Flaxman formations, the Belfast, Skull Creek and Pember mudstones, and mudstones and marls of the Wangerrip, Nirranda and Heytesbury groups. Play types include faulted anticlines, large anticlinal features and tilted fault blocks.