Exploring the Beetaloo: will Australia's first viable shale play be sourced by billion year old gas?

Abstract

Origin Energy completed exploration campaigns in 2015 and 2016 in the Beetaloo Sub-basin of the Greater McArthur Basin in the Northern Territory, drilling three vertical wells and one horizontal well. These wells have provided a wealth of technical data to assist in the characterisation of the primary source rock reservoirs or ‘shale gas’ plays in the Basin – the Velkerri Formation Play and the Kyalla Formation Play. In this paper we demonstrate the presence of thick, gas saturated and over-pressured source rocks across the sub-basin. In addition to the drilling campaign, the multi-stage hydraulic fracture stimulation of the Amungee NW-1H horizontal well was completed in 2016 – this operation was unique as it represents the first horizontal stimulation operation in the Beetaloo Sub-basin and the longest ‘plug and perf’ type horizontal completion in Australia. Data from the extended production test of the Amungee NW-1H are critical from a technical and, potentially, economic and political perspective. In addition to the technical work program, Origin has undertaken preliminary environmental baseline studies and substantial stakeholder engagement. Ensuring environmental baseline data are available is key to demonstrating that onshore gas developments can be undertaken without adverse environmental outcomes, and also for gaining social acceptance. However, data and facts alone are not sufficient to build community confidence. Origin has engaged extensively with pastoralists, local communities and Traditional Owners to build direct relationships and partnerships that encourage acceptance of the gas industry’s ability to coexist and deliver mutual benefits to the businesses and communities of the Barkly region and the Northern Territory more broadly.

A very unconventional hydrocarbon play: The Mesoproterozoic Velkerri Formation of northern Australia

“…1.40-1.34 Ga Velkerri Formation and the ca. 1.34-1.31 Ga Kyalla Formation (Jackson et al, 1986;Crick et al, 1988;Page et al, 2000;Kendall et al, 2009;Cox et al, 2016;Spinks et al, 2016;Close et al, 2017;Revie, 2017;Baruch et al, 2018;Yang et al, 2018).…”

“…2). The Velkerri Formation continues to generate substantial interest as an unconventional gas play (Close et al, 2017;Revie, 2017;Baruch et al, 2018); however, the Kyalla Formation also has potential as an oil and gas target (Baruch et al, 2018;Revie and Normington, 2020). Minor oil and gas shows have been identified in wells intersecting Roper Group strata (Table 1) with significant oil shows from the Jamison 1 petroleum well (Jamison sandstone reservoir), that are likely sourced from the Kyalla Formation (Lannigan and Torkington, 1991;Jarrett et al, 2019c;).…”

“…Additionally, oil bleeds in Urapunga 4 are self-sourced from the Velkerri Formation (Jackson et al, 1986). Significant gas shows in Shenandoah 1A and recent hydraulic fracturing of the Velkerri Formation in Amungee NW-1H confirmed substantial gas flows are possible (Close et al, 2017). Recent resource assessments of the Kyalla and Velkerri formations estimates an in-place resource of 429 million barrels of oil (MMbbls) and between 8 and 118 trillion cubic feet of gas (Tcf) (Revie, 2017;Schneck et al, 2019).…”