Changes

Biomarkers studies indicate that the depositional organic matter is derived from biomass dominated by bacteria with minor input from archaea and eukaryotes<ref>Jarrett, A. J., G. M. Cox, J. J. Brocks, E. Grosjean, C. J. Boreham, and D. S. Edwards, 2019, Microbial assemblage and palaeoenvironmental reconstruction of the 1.38 Ga Velkerri Formation, McArthur Basin, northern Australia: Geobiology, vol. 17, no. 4, p. 360-380.</ref>. Total organic carbon (TOC) content of the Amungee Member varies across the basin: along the northern margin of the basin where the formation is shallowly buried, TOC can be as high as 20 wt% and thermal maturity indicators are consistent with early liquid hydrocarbon generation. In the deeper central parts of the basin TOC of the organic-rich intervals reduced to ca. 2-4 wt% and maturity indicators are consistent with dry gas generation (Faiz et al., 2016; Delle Piane et al., 2020; Hall et al., 2020). Organic geochemistry laboratory results summarized by Hall et al. (2020) indicate excellent source rock potential for the oil-prone organic-rich intervals of the Velkerri Formation with hydrogen index as high as 800 mg HC/g TOC. Peak hydrocarbon generation is estimated to occur at thermal maturity quantified by average equivalent vitrinite reflectance of 0.95 %EqVR (equivalent vitrinite reflectance) and onset of generation occurs at maturities between 0.44 %EqVR and 0.82 %EqVR (Hall et al., 2020).

Biomarkers studies indicate that the depositional organic matter is derived from biomass dominated by bacteria with minor input from archaea and eukaryotes<ref>Jarrett, A. J., G. M. Cox, J. J. Brocks, E. Grosjean, C. J. Boreham, and D. S. Edwards, 2019, Microbial assemblage and palaeoenvironmental reconstruction of the 1.38 Ga Velkerri Formation, McArthur Basin, northern Australia: Geobiology, vol. 17, no. 4, p. 360-380.</ref>. Total organic carbon (TOC) content of the Amungee Member varies across the basin: along the northern margin of the basin where the formation is shallowly buried, TOC can be as high as 20 wt% and thermal maturity indicators are consistent with early liquid hydrocarbon generation. In the deeper central parts of the basin TOC of the organic-rich intervals reduced to ca. 2-4 wt% and maturity indicators are consistent with dry gas generation (Faiz et al., 2016; Delle Piane et al., 2020; Hall et al., 2020). Organic geochemistry laboratory results summarized by Hall et al. (2020) indicate excellent source rock potential for the oil-prone organic-rich intervals of the Velkerri Formation with hydrogen index as high as 800 mg HC/g TOC. Peak hydrocarbon generation is estimated to occur at thermal maturity quantified by average equivalent vitrinite reflectance of 0.95 %EqVR (equivalent vitrinite reflectance) and onset of generation occurs at maturities between 0.44 %EqVR and 0.82 %EqVR (Hall et al., 2020).

Mineralogical analyses, geo-mechanical laboratory tests and down-hole fracture tests conducted so far indicate that the organic rich mudstones of the Amungee Member have good reservoir and completion qualities that should result in brittle behavior conductive to fracture propagation (e.g. Santos 2017).

Mineralogical analyses, geo-mechanical laboratory tests and down-hole fracture tests conducted so far indicate that the organic rich mudstones of the Amungee Member have good reservoir and completion qualities that should result in brittle behavior conductive to fracture propagation<ref>Santos Ltd., 2017, [https://frackinginquiry.nt.gov.au/submission-library Submission 168 to the Scientific Inquiry into Hydraulic Fracturing in the Northern Territory.]</ref>.

Hydrocarbon exploration in the McArthur Basin began in the 1980s targeting conventional oil accumulations in structural and stratigraphic traps. Although several shows were identified, no commercial discoveries were made. Following the unconventional oil/gas success in North America, exploration in the Beetaloo Sub-basin has focused on unconventional hydrocarbon resources in the Mesoproterozoic Roper Group. More than 30 petroleum wells have been drilled in the Beetaloo Sub-basin and surrounding areas of the greater McArthur Basin (Fig. 1) and approximately half of these wells have been drilled in the last ten years.  

Hydrocarbon exploration in the McArthur Basin began in the 1980s targeting conventional oil accumulations in structural and stratigraphic traps. Although several shows were identified, no commercial discoveries were made. Following the unconventional oil/gas success in North America, exploration in the Beetaloo Sub-basin has focused on unconventional hydrocarbon resources in the Mesoproterozoic Roper Group. More than 30 petroleum wells have been drilled in the Beetaloo Sub-basin and surrounding areas of the greater McArthur Basin (Fig. 1) and approximately half of these wells have been drilled in the last ten years.  

* Santos Ltd (2017) Submission 168 to the Scientific Inquiry into Hydraulic Fracturing in the Northern Territory. Viewed 25 March 2019, https://frackinginquiry.nt.gov.au/submission-library.

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