ABSTRACT: Timor Sea Structural Styles

WOODS, EDWARD PHILIP, Norgen International Ltd., Sydney, Australia

The Vulcan subbasin of the Australian Continental Margin is divided into different structural domains by major Transfer Zones, which developed during the Late Jurassic rifting phase. Numerous third-order transfers within each domain compartmentalize the major northeast-trending normal fault blocks. This results in formation of structural traps, but also affect hydrocarbon migration pathways.

Several fault styles were formed during the Late Jurassic and these have a predominant northeast-soutwest orientation. Several levels of detached faults are recognized across the basin, and overprinting these are block-faults that produce titled fault blocks or horsts and

grabens. A distinctive feature of the Jabiru Terrace is the formation of "hourglass" structures formed by conjugate faulting.

Early hydrocarbon entrapment is enabled by an intra-Cretaceous fault episode that formed the basis for many of the present prospects.

A predominantly extensional fault reactivation episode occurred during the Late Miocene/Early Pliocene. This episode resulted in formation of new traps and modification of older traps. This late structuring produces a complex structural interaction that needs to be understood in order to find more discoveries in this prospective basin.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)