Formation evaluation case study: Glyde unconventional Middle Proterozoic play in the McArthur Basin, northern Australia

Abstract

The Glyde–1 and Glyde Sidetrack–1 wells were drilled by Armour Energy in the Glyde Sub-basin of the McArthur Basin, NT, Australia in August 2012. This program was to evaluate the unconventional hydrocarbon potential of the Barney Creek Shale source rock and the conventional potential of the Coxco Dolomite of the McArthur Group. The Glyde wells discovered gas in both formations. Transtensional faults in this region allowed to form a series of fault-bounded depocentres. The target gas source of the Glyde discovery is located in 1640 Ma organic-rich black shales of the Barney Creek Formation. Weatherford was contracted to acquire both vertical and lateral advanced log suites and perform subsequent log interpretation to constrain the in situ minimum and maximum horizontal stress regimes to assist with maximising gas production from future lateral placement pilot programs in the Coxco Hydrothermal Dolomite (HTD) Play. Two stratigraphic and structural domains were defined by the observed features in the image log data; a dolostone dominated, fractured strata below an erosional surface. Above this stratigraphic timeline is a monotonous package of laminated, lower-energy Barney Creek Formation sediments. Observed changes in azimuths and dips of the measured beddings suggest a phase of compression after deposition of the Barney Creek Formation, resulting in gentle folding of the formations. The porous gas-charged HTD play is drilled in top of the anticline, which is further characterised by a significant number of conductive fractures, likely indicative of open fractures.