--> --> Abstract: An Integrated Approach to Evaluating Source Potential in the Timor Sea, Offshore Australia, by C. A. Walsh; #91015 (1992).

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ABSTRACT: An Integrated Approach to Evaluating Source Potential in the Timor Sea, Offshore Australia

WALSH, C.A., Conoco Inc., Houston, TX

Standard organic geochemical assessment was combined with detailed biomarker analysis and maturation/generation modeling in an evaluation of Upper Jurassic and Lower Cretaceous intervals in the Timor Sea area, Northwest Shelf Australia. Analyzed samples included cuttings from eight shaly intervals and two coal layers, and one drill stem test oil sample. Two Cretaceous shales, six Jurassic shales, and one Jurassic coal have fair to excellent potential for liquid petroleum generation. The organic matter is typically a mixture of marine and terrestrial components. The other Jurassic coal is characteristic of an excellent gas-prone source rock. The oil is dominated by a terrestrial signature relative to the mixed marine/terrestrial character of the source rocks. The ratio of biomarker com ound x (previously documented as a terrestrial indicator in other Australian source rocks), to C29 hopane compound x was ten times greater in the oil than in the source rocks examined. Furthermore the oil sample is more mature than the potential source rocks examined here. Therefore, a more mature terrestrially dominated facies is invoked as the source of this oil.

The study also included the application of maturation and hydrocarbon generation modeling to define the areal distribution of mature source rocks in the Upper Jurassic and Lower Cretaceous section. Kerogen to hydrocarbon transformation kinetics were analytically determined for eight of the potential source rocks and applied in the

modeling phase of the study. Three distinct groups of kerogens were defined based on their dominant energy components. The net effect of interlayering these potential source intervals will be an expanded liquid generation zone with respect to time and depth.

 

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)