Publication Name: PESA's Eastern Australasian Basin Symposium II
Authors: V. Stagpoole, R. Funnell and A. Nicol
Date Published: December 2004
Number of Pages: 27
Reference Type: Book Section
Abstract:
The Taranaki Fault is a crustal scale thrust fault forming the eastern margin of the Taranaki Basin. The fault, extending for over 400 km with 5-10 km of vertical and 10 km of horizontal displacement, has been the target of intensive petroleum exploration. New detailed seismic interpretation indicates that periods of rapid deformation and reverse displacement occurred primarily during the Mid-Late Eocene (ca. 43-35 Ma) and the Early Miocene (ca. 23- 18 Ma), with a southward migration in the locus of activity with time. In conjunction with modelling, new seismic interpretation has improved definition of the complex geometry and helped to constrain the charge history for associated petroleum accumulations. Oil and gas generation is predicted from Cretaceous source rocks to the north and south of the Taranaki Peninsula, prior to trap formation, with westerly dipping sedimentary strata focussing migration towards the principal slip surface of the fault. On the peninsula, primarily oil generated from Palaeogene source rocks in the vicinity of the fault is predicted to migrate mainly westwards away from the fault towards the Tarata Thrust Zone. The complex nature of faulting, however, means that a large variety of trapping styles, reservoir intervals and potential seals are present-leading to a diversity of petroleum systems. The irregular nature of the hanging wall in~icates that traps associated with the principal slip surface are likely to be relatively small (<50 MMBBLs in-place), although there is potential for multiple stacked plays and for larger single accumulations westward of the fault and in the north.