Phoenix South: A New Petroleum System in the Bedout Sub-Basin

Triassic petroleum systems on the central North West Shelf – Learnings from the greater Phoenix area seismic mapping and geochemical studies

“…The Phoenix 1 gas discovery has been reinterpreted as an oil discovery based on the results in Phoenix South 1 and re-evaluation of the Phoenix 1 log data (Thompson et al, 2018). The geochemical composition of the Phoenix South 1 oil reservoired in the TR15 sequence is consistent with derivation from a Triassic source rock deposited in a paralic/deltaic environment (Thompson et al, 2015;Grosjean et al, 2018). The oil is distinct from the Lower Triassic oils of the Perth Basin, which are derived from the earliest Triassic anoxic marine Hovea Member source rock.…”

“…The loss of the gas within the Phoenix South 1 fluid may have resulted in the formation of oil in the reservoir. Carbon isotopic analyses combined with biomarker data indicate that the Phoenix South 1 oil has unique characteristics compared to other oils of the NWS and represents a new petroleum system (Thompson et al, 2015;Grosjean et al, 2018). In addition, hydrocarbons discovered in Roc 2 are typed to organic-rich oil-prone core samples of lagoonal facies encountered in the same well (Woodward et al, 2018).…”

“…Smith et al (1999) placed source rock units in the Locker Shale and Keraudren Formation within the Westralian 1 Petroleum System. The existence of multiple effective fluvial-deltaic source rocks within the Keraudren Formation in the Bedout Sub-basin (Thompson et al, 2015;, in addition to the prolific gas-prone source rocks of the Mungaroo Formation in the northern Carnarvon Basin, necessitates redefining the Triassic petroleum system nomenclature. The regional correlation of time-equivalent…”