ABSTRACT: A Review of the Hydrocarbon Generating Potential of Some Terrestrial Source Rocks with Special Reference to the Surat Basin, Eastern Australia

H. M. Hawlader

Oil and gas in most Australian basins are thought to have been derived mainly from land-plant-sourced organic matter, the overall gas-prone nature of the Australian petroleum provinces being due principally to the presence of continental source rocks. However, oil, gas, and condensate have been discovered in various basins around the world in situations where they have been sourced from terrestrially derived organic matter and at maturity levels normally regarded as prohibitive to hydrocarbon generation according to conventional wisdom. The petrological and geochemical nature of some terrestrially derived organic matter (notably suberinite and terpene resinites) of the Surat basin suggest that it can produce significant amounts of liquid hydrocarbon at a very early stage f maturation. Additionally, abundant quantities of methane and possibly higher hydrocarbons (i.e., C₂₊) could be generated from hydrogen-poor type III organic matter in the diagenetic stage before it reaches the threshold of oil generation. In the light of these new data and concepts, a multiple source for the Surat Basin reservoired oil and gas is suggested. Knowledge of this

kind may be useful in the exploration for new fields in this basin and in other partially explored and unexplored frontier basins with similar geologic and geochemical characteristics.

AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990