Although the search for hydrocarbons in Indonesia was initiated about 8 decades ago, exploration work is still at a high level. Recent studies have resulted in a new understanding of the Tertiary sedimentary basins, and knowledge concerning offshore sedimentary basins has been updated significantly. More important, however, is the current knowledge of the mechanisms of basin formation which seems to enhance the validity and applicability of the new global tectonics to the geology of Indonesia.

Recent exploration surveys and subsequent drilling have shown that the southern part of the Sunda Shelf consists of many sedimentary basins and intervening uplifts. Major faults are common throughout the area and clearly control the distribution and shapes of the basins. Block faulting apparently broke up the periphery of the Sunda Shelf at the beginning of Tertiary time. The chief crude oil production in western Indonesia is from the regressive and deeper transgressive sandstone series of Oligocene-Miocene age, except in East Kalimantan, where producing zones range from Eocene to Pliocene.

Prospective areas have changed considerably since oil and gas in economic amount have been proved from an interbedded limestone formation of Tertiary age. Additional reserves are anticipated in stratigraphic traps.

Oil and gas discoveries within deltaic sandstones, notably in East Kalimantan, have upgraded significantly the onshore and offshore potentials of the area. Carbonate rocks are becoming a prime objective in the search for oil, especially in the East Java-Madura basinal area.

Although eastern Indonesia was chiefly the site of late Paleozoic and Mesozoic sedimentation, oil has been proved only within the strata of Tertiary age, notably in the Salawati basin. Of particular importance was the recognition of the tremendous potential that reefs, particularly Tertiary reefs, possess as hydrocarbon reservoirs. A similar basin and environmental model is anticipated for the Bintuni basin.

Recent scientific cruises have indicated the presence of several potential basinal areas between the Sunda and Sahul Shelves.

The sedimentary basins in Indonesia can be classified as arc-front, foreland, and deltaic basins.