Assessment of continuous oil and gas resources in the Beetaloo Basin, Australia, 2018

The U.S. Geological Survey (USGS) quantitatively assessed the potential for undiscovered, technically recoverable continuous oil and gas resources in the Beetaloo Basin of northern Australia (fig. 1). The Mesoproterozoic Roper Group in the basin contains the Velkerri and Kyalla Formations, two organic-rich source formations that possibly form some of the oldest viable petroleum systems in the world (Jackson and others, 1986; Silverman and Ahlbrandt, 2011; Cox and others, 2016). The shale units of the Velkerri and Kyalla were deposited between 1,400 and 1,300 million years ago (Yang and others, 2018). Limited drilling and production testing have shown that these rocks may contain recoverable oil and gas resources (Close, Cote, and others, 2017). For rocks of this age to potentially contain recoverable oil and gas indicates that throughout the long period between the Mesoproterozoic and the present, there has been limited deformation of the Beetaloo Basin, and generation might have been relatively late in the burial history. However, the tectonic evolution of the Mesoproterozoic Beetaloo Basin is largely unknown, and several hypotheses have been advanced that include rift basin, multiphase intracontinental basin, foreland basin, and epicontinental basin development (Silverman and Ahlbrandt, 2011; Cox and others, 2016; Close, Cote, and others, 2017; Yang and others, 2018). Rocks of the Roper Group have not been thermally stressed beyond the gas-generation window (Close, Baruch, and others, 2017).