--> Stratigraphic Evolution of the Barrow Deltas, Northern Carnarvon Basin, North West Shelf, Australia

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Stratigraphic Evolution of the Barrow Deltas, Northern Carnarvon Basin, North West Shelf, Australia

Victorien Paumard1, Julien Bourget1, Annette George1, Tobias Payenberg2 and Bruce Ainsworth2

1Geology, Centre for Petroleum Geosciences and CO2 Sequestration, School of Earth and Environment, The University of Western Australia, Crawley, WA, Australia.
2Stratigraphy, Chevron ETC, Perth, WA, Australia.

September 15, 2015 Tuesday 1:45 P.M. International Conference & Exhibition, Melbourne, Australia

Abstract

The Northern Carnarvon Basin, covering a surface of ~535 000 km2, is located on the North West Shelf and constitutes the most developed hydrocarbon province of Australia. The Barrow Group represents a deltaic to turbiditic slope/basin floor depositional systems of Berriasian–Valanginian age, with gas fields discovered in both shallow marine and basin-floor fan reservoirs. During the late syn-rift phase of basin extension, several very wide (>100 km) deltas prograded to the north–northwest in the Exmouth and Barrow sub-basins, as well as along the Exmouth Plateau. The deltaic and basin-floor systems prograded over half-graben and were overlain by a thick transgressive shale that forms the regional seal. Here we use regional 2D, 3D seismic and well data to constrain the seismic stratigraphic evolution (2nd to 3rd order scales) of the deltaic systems temporally and spatially. The spatial extent of each delta is identified via offlap break mapping. At higher resolution, the internal architecture of individual deltas (including mapping of delta plain and delta front from identification of depositional elements and linkages with the deep-water elements) is interpreted using seismic geomorphological analysis of several 3D seismic volumes. This regional approach highlights the relative role of the external factors (eustasy, tectonism, accommodation, sediment supply) that controlled the stratigraphic architecture of the Barrow Group at basin-scale. The Barrow Group deltas formed during the transition between an active rift and a passive margin, and the complex tectonic configuration of the North West Shelf during the Early Cretaceous period played a key role in the spatial distribution of the deltas (lobe switiching) as well as in the source of sediment and the creation of accommodation space in the basin.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015