Facies architecture of the K10 supersequence in the Browse Basin: when sequence stratigraphy meets lithostratigraphy

Abstract

Regional seismic sequence stratigraphic mapping of the K10 supersequence (Berriasian–Valanginian) has brought into focus the relationship between sequence stratigraphic and lithostratigraphic units. In this extended abstract, the relationship between seismically-defined sandstone bodies and the Brewster Member, an important exploration target and reservoir in the Browse Basin, is investigated. Deposition of the K10 supersequence started at the onset of rifting between Greater India and the Northern Carnarvon Basin. Sediment sourced from uplifted areas resulted in deposition of the Barrow Delta in the Exmouth and Barrow sub-basins. In the Browse Basin, K10 is also a sand-rich progradational sequence, albeit diminutive compared to the Barrow Delta. Seismic mapping of K10 in the Caswell Sub-basin has resolved stratal geometries and, with the integration of well data, recognition gross depositional facies. Sandstone-prone siliciclastic platform facies (clinoform topsets) include the Brewster Member. The first reference to the Brewster Member in the Australian Stratigraphic Units Database applied the name to the upper part of the K10 sequence between 3,284 m and 3,405 m in Heywood–1. Usage of this name, however, has been inconsistently applied to sandstone-prone units within K10. Given the significance of the Brewster Member as an exploration target, and as a reservoir in the Ichthys-Prelude and Burnside gas fields, attention to integration of sequence stratigraphic and lithostratigraphic frameworks for this interval is timely.