Australia
Offshore / Exploration
Envoi has been engaged by Perth-based ASX-listed Top End Energy (“TEE”), to assist in their search for a partner for their three 100% operated Permits, EP153, EP154 and EP144, in the Northern Territory, onshore NW Australia. These are situated in the highly prospective Beetaloo Basin and analogous but undrilled South Nicholson Basin. Of the 20 or so wells drilled in the Beetaloo to date, most are old stratigraphic or mining boreholes drilled before the unconventional resource play boom in the USA after 2010.
The 28,000 km2 Beetaloo Basin is an intra-cratonic sub-basin of the greater McArthur Basin, and consists of stacked fluvio-deltaic to nearshore and shallow marine Mesoproterozoic resource play sediments which make up the Roper Group. Four stacked reservoirs, comprising two zones of the Velkerri Formation, plus the Kyalla and Hayfield formations are defined. The most recent wells have targeted the 900 m thick Kyalla Formation, with some extending deeper, between 2,000 – 2,500 m deep, into the Velkerri Formation. This covers an area of over 11,900 km2 and has net pay up to 270 m thick. The richest resource play stratigraphy is in the mid Velkerri B shale with a consistent thickness of around 40-60 m and TOCs ranging between 2-6%. The brittle nature of the lithology and over pressure also enhances flow rates when stimulated. The Beetaloo’s Middle Velkerri formation of the basin from wells which have flowed over 17 MMcfd on test. It is publicly reported as capable of producing an estimated 118 – 293 Tcf gas potential (with individual wells expected capable of producing around 10 Bcf over 10+ years). It compares favourably to the 225-248 Tcf from the bigger 160,000 km area of the Marcellus shale in the USA. This indicates that the huge potential of the Beetaloo Basin and other NT plays, including in the South Nicholson Basin, could collectively be at least as or even more productive than per unit area most proven US resource plays. The large multi-TCF Shenandoah play development in the Beetaloo basin depocentre granted final investment approval (FID) for its A$180 MM development in September 2025 and the large development of the Carpentaria field granted FID in December 2025, further demonstrate the huge potential of the Beetaloo Basin plays.
Licences EP153 and EP154 lie over the unexplored northern extension of the proven Beetaloo Basin plays to the south and east. Three historical wells exist in the southern part of EP153, all drilled in the 1980s. These stratigraphic or shallow conventional exploration wells were drilled on old one line seismic leads and all encountered shows in the key unconventional plays now proven by drilling and the large developments across the Beetaloo basin area.
EP144 lies to the south and straddles the highly prospective margin of the large but untested South Nicholson Basin where two formations, the Lawn Hill Shale and the Riversleigh Shale Formations are the primary targets, with shows in the one key stratigraphic well and up to 3.1wt% TOC in mineral wells confirming maturity and lateral extent. In addition to the unconventional gas plays, historical wells suggest that commercial quantities of very high value helium and also hydrogen are likely to be present in any gas that is produced, and could add substantially to the revenue potential, even at low concentrations. A large new gas export pipeline is planned to cross EP144, reducing export access cost.
TEE is now offering a material interest in each licence by funding the planned forward work programmes in each, involving new seismic, geochemical and gradiometry surveys (Est. likely to cost US$ 0.5 million each) with the option to progress to the next exploration term and drill one well in each permit (Est. US$ 1.35 million each).
