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ABSTRACT: Structure and Hydrocarbons: New Guinea Fold Belt

Hill, Dr. Kevin C., Jeffrey T. Keetley, R. Dan Kendrick, and Edy Sutriyono , La Trobe University, Melbourne, Victoria, Australia

Seismic, borehole and field data acquired over the last ten years demonstrate that the structural style in the Papuan Fold Belt comprises inverted basement extensional faults and asymmetric detachment folds that break through the overturned forelimb. The previous fault-bend fold model was flawed due to lack of data and inappropriate analogues that ignored the mechanical stratigraphy. In the oil province of Papua New Guinea, the deformation front has not yet impinged on strong Australian lithosphere, so a relatively low fold belt occupies its own foreland basin. The adjacent gas-condensate province in the western Papuan Fold Belt has just impinged on the strong lithosphere, developing a foreland basin and basement-cored anticlines. Along strike in the Irian Jaya Fold Belt, the deformation front has encountered the buttress of the strong Australian lithosphere causing a 15 km thick Palaeozoic and Mesozoic sequence to be thrust to surface along a previously extensional, basin-margin fault. Focussing deformation on one fault has created mountains 5 km high and an adjacent foreland basin. Structures in the mountains are breached, but the adjacent foreland basin has hydrocarbon potential. The poorly known Lengguru Fold Belt resembles the oil province in the Papuan Fold Belt, but Pleistocene extensional faulting may have caused breaching. In addition, deep burial by thick Tertiary carbonates has destroyed Mesozoic reservoir porosity, except in the north, where further discoveries like the 30 tcf Tangguh gas province are possible.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia