New insights into reservoir sand provenance in the Exmouth Plateau and Browse Basin

Abstract

A pilot study to determine if zircons present in reservoir facies of the North West Shelf can be used to identify provenance and sediment transport pathways has analysed samples from three wells: Guardian–1 and Hijinx–1 (Carnarvon Basin), and Burnside–1 (Browse Basin). Operating companies Chevron, Santos and Hess collected 3–5 kg of cuttings from sandstone bodies intersected in the three wells. Samples were sent to Geoscience Australia for zircon separation and analysis at the Geochronology Laboratory on a sensitive high-resolution ion microprobe (SHRIMP). To provide a statistically meaningful representation of ages in each sample, 70–80 grains were randomly selected for analysis. During the past 20 years, Geoscience Australia and the state geological surveys of WA, NT, Queensland and SA, together with the ANU, UWA and Curtin University, have analysed zircons found in igneous and sedimentary rocks that outcrop in WA and central Australia. This analysis has been done to determine the ages of emplacement, extrusion or maximum depositional ages. This dataset permits the ages of potential onshore provenance areas to be differentiated; hence, correlations can be made between zircons contained within the transported sands and their potential source regions from onshore Australia. In this extended abstract, the spectrum of ages in each sample will be shown, and potential provenance and sediment transport pathways will be discussed. The abstract concludes with the outline of a 2–3 year project to obtain a dataset that will provide a regional stratigraphic and spatial coverage of the North West Shelf for provenance studies.