--> ABSTRACT: The Evolution and Hydrocarbon Habitat of the Papuan Fold Belt, PNG, by David G. Dalton, R. I. Smith, S. J. Cawley; #91003 (1990).

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ABSTRACT: The Evolution and Hydrocarbon Habitat of the Papuan Fold Belt, PNG

David G. Dalton, R. I. Smith, S. J. Cawley

After over 70 years of hydrocarbon exploration in the Papuan fold belt of PNG (Papua New Guinea) there have been a number of hydrocarbon discoveries over recent years that have confirmed its potential as a significant producing province.

The Papuan basin developed during the early Mesozoic as part of the northeast corner of the Australian passive margin. The basin's Tertiary evolution and the development of the Papuan fold belt within the Papuan basin has evolved in response to oblique convergence between the northerly moving Australian plate and westerly moving Pacific plate.

Restacking of the Mesozoic passive margin sequence within the Papuan Basin was initiated in the early Miocene by southward abduction of the Solomon Sea plate and the subsequent collision, in the late Miocene, of the Melanesian Island arc along the northeastern margin of PNG. This later collision provided the driving mechanism for the development of the papuan thrust belt.

To date, all the significant hydrocarbon discoveries made within the Papuan fold belt have been located within the frontal zone of the fold belt, which is characterized by relatively simple ramp anticlines and thick-skinned inversion structures. The primary proven reservoir fairway is the Jurassic Toro Formation, which is a sequence of stacked submarine bars prograding out across a shallow-marine low-gradient shelf.

Geochemical analysis of produced hydrocarbons and samples collected from the many surface seeps found in the fold belt indicate two main families of oil. A model explains the distribution of hydrocarbons discovered to date, which involves Jurassic and Cretaceous source intervals and a complex history of secondary migration and entrapment.

The unique technical problems associated with exploration of the Papuan fold belt leave many elements of the proven play systems uncertain, but in so doing, they present many challenges and opportunities for the future.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990