A Re-Assessment of the Petroleum Potential of the Darling Basin: A Discovery 2000 Initiative

Abstract

New data, including regional high resolution aeromagnet ic coverage, acquired by the New South Wales Department of Mineral Resources (DMR) as part of its Discovery 2000 Initiative, have provided the first opportunity for a comprehensive review of the regional framework of the Darling Basin. Covering an area of 90,000 km2 in central western NSW, the Darling Basin contains over 8,000 m of mainly Palaeozoic sediments. With only 17 petroleum wells drilled in the basin, mostly during the 1960s and 1970s, and some 1,550 km of modern multifold seismic coverage, the Darling Basin represents one of the major frontier basinal regions of onshore Australia.The initial phase of petroleum exploration was discouraged by the lack of shows, the likelihood of gas-prone source rocks and presence of a thick, red-bed dominated, organically lean, Late Devonian sequence. Renewed interest in the Darling Basin's prospectivity followed from favourable, albeit superficial, comparisons between the Darling Basin and Queensland's Adavale Basin, where commercial gas is produced at the Gilmore Gas Field. Additionally, as part of some $15 million expenditure by the DMR on acquiring new and reassessing old data from the Darling Basin, new geochemical analyses of extracts collected from core holes and out-crop suggest the presence of at least one active Palaeozoic petroleum system. This system has been responsible for generating oil and possibly substantial quantities of gas found dissolved within artesian waters in the overlying shallow Mesozoic sequences.

Lithostratigraphic and sequence stratigraphic architecture of the Winduck Interval, central Darling Basin, Australia, based on integration of wireline logs, cores and cuttings data

“…3), which is regarded as the stratigraphic reference section for the Winduck Interval because of its extensive core coverage (intersected from 378 m to the termination depth of 1224 m) and the relatively complete stratigraphy preserved in this location. The complex stratigraphy in the Blantyre and western Neckarboo Sub-basins has been illustrated in previous publications (Bembrick 1997a, b;Alder et al 1998;2005, 2006a, b, 2010Cooney & Mantaring 2007;Khalifa & Ward 2009;Khalifa & Alta'ee 2011).…”

“…The stratigraphy of the Darling Basin has been summarised by Bembrick (1997a, b), Alder et al (1998) and other authors and is adopted herein. Bembrick noted that prior literature contained a 'terminological maze' of often-conflicting strato-tectonic terms to describe the various lithofacies in the basin.…”

“…However, the basic and most widely accepted published stratigraphic framework for the Darling Basin, western New South Wales, has been derived from Evans (1977), Byrnes (1985), Glen (1979Glen ( , 1982aGlen ( , b, 1986, Neef et al (1989), Neef & Bottrill (1991), Bembrick (1997a, b), Alder et al (1998), Cooney & Mantaring (2007, Khalifa (2005Khalifa ( , 2006aKhalifa ( , 2007 and Khalifa & Ward (2009). Wide varieties of lithostratigraphic unit names have been used to describe distinct sedimentary units, many of which are laterally discontinuous.…”

“…8) was constructed using the top of Winduck Interval or equivalent unconformities in each well as a datum (see Alder et al, 1998;Clark et al, 2001;Khalifa 2005;Khalifa & Ward 2009). This horizon is a distinct lithologic break.…”

“…Among the earliest publications are those by Neef and Bottrill (1991), Alder et al (1998), Bembrick (1997a, b), Neef (2004Neef ( , 2005 and Cooney & Mantaring (2007). The integration of sedimentology and stratigraphy has recently focussed on in sequence stratigraphic papers by Willcox et al (2003), Khalifa (2005Khalifa ( , 2006a, Khalifa & Ward (2009) and Khalifa & Alta'ee (2011).…”