Basin-to-prospect-scale subsurface characterisation: new insights into the Exmouth Sub-basin, North West Shelf, Australia

Abstract

The Exmouth Sub-basin represents part of the intracratonic rift system of the northern Carnarvon Basin, Australia. Hydrocarbon exploration has resulted in the discovery of a variety of oil and gas accumulations, mainly in Upper Triassic, Upper Jurassic and Lower Cretaceous intervals. Recent 3D petroleum systems modelling aided in understanding the interaction of the complex basin evolution and hydrocarbon charge history, shedding light on the variety and distribution of hydrocarbon types encountered, whilst also highlighting future remaining potential in both proven and untested plays. As a result of this modelling, the Exmouth Subsurface Characterisation Study was commissioned to further leverage >12000km2of recently acquired and processed seismic data and integrate data from specifically conditioned wells from across the Exmouth Sub-basin. The primary study objective was to better understand the distribution of lithologies across the basin, with focus upon the reservoir presence and properties over proven and potential deeper sections. Furthermore, given the variety of hydrocarbon types encountered, this study set out to understand the amplitude behaviour of these types within the different reservoirs. Collectively, these results have aided in identifying analogous hydrocarbon amplitude responses across the basin, derisking identified plays, prospects and existing discoveries and fields whilst also identifying new plays and leads.