ABSTRACT: Korean Offshore Basins and Australian Gippsland Basin--a Comparison of Their Nonmarine Petroleum Potential
H. Y. Kim, A. C. Cook
Until comparatively recently, nonmarine source rocks were not generally considered to be source rocks for oil. However, studies of some Australian, Chinese, and Indonesian basins have indicated that hydrocarbons can be derived from land-plant-dominated organic matter and even from coal seams. The southern parts of the Korean Continental Shelf and the Australian Gippsland both contain thick nonmarine sedimentary sequences. Both basins have similar geological settings, depositional environments, and burial thickness. In this paper we show that the role of coal and coal-related dispersed organic matter of liquid hydrocarbon deserves further petrographic and geochemical study.
In Gippsland, geochemical and petrological studies indicate that vitrinite, cutinite, sporinite, liptodetrinite, and suberinite all constitute significant sources of migrated liquid hydrocarbons. The general form of the relationship between the extract yield and reflectance indicates peak extract yields in the range 0.45% to 0.6% reflectance. This may support petrographic evidence that generation of significant amounts of oil occurs in the Gippsland basin at low maturation levels, but some extract data indicate a deeper contribution from more mature source rocks.
The most important differences between the both basins is that the Gippsland basin contains thicker coal measures and greater volumes of source rocks. These differences are probably caused by different paleoclimates and tectonic settings. Therefore the greatest potential within the Korean succession probably occurs where the coals are best developed, and the establishment of the distribution of the coals will assist in oil and gas exploration.
AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990