BPH Energy (ASX: BPH) has revealed further key findings from an ongoing review of historical data covering investee company Advent Energy’s PEP 11 petroleum permit in the offshore Sydney Basin.
Last week, the company announced the identification of 10 structural leads in four structural provinces within the permit area, with a total potential of 1 trillion cubic feet (TCF) of gas-in-place.
Today, BPH said the review has identified a further key report prepared by prior tenement holder Ampolex that shows the “Baleen South” lead was one of its major targets and modelling had predicted the single structure alone could hold 1.5TCF of estimated unrisked reserves.
Ampolex’s report, which dates back to 1992, also said the primary source rocks “could provide a viable, mature, gas/condensate source along the length of the Offshore Uplift”.
Ampolex, which delisted from the ASX after being taken over by Mobil Corporation in the 1990s, previously held the tenement area in joint venture with Australian gas major Santos (ASX: STO).
BPH owns 22.7% of Advent Energy, which holds an 85% stake in PEP 11. Bounty Oil and Gas (ASX: BUY) owns the remaining 15% interest in the offshore permit.
Advent and Bounty have previously identified Baleen, located 30km south of Newcastle, as a primary structural target and last month applied for a drilling permit with the National Offshore Petroleum Titles Administration (NOPTA).
The Ampolex report refers to a target named “Baleen South” located some 30km south-southeast of Newcastle on the crest of the “Offshore Uplift”.
According to the report, the structure was mapped with 1991 seismic data and unrisked reserves were estimated at 1.56TCF of gas; risked gas reserves were estimated at 112 billion cubic feet.
Other findings from the report confirmed the primary source rocks, the late Permian coal measures, could provide a “viable” and “mature” gas and condensate source.
The primary target reservoir in the offshore Sydney Basin is the Hawkesbury sandstone and “excellent” top seal would be provided by the Wianamatta Group shales and/or the Newport formation tidal shales, the Ampolex report read.
Further seismic studies
Since Ampolex’s study, further seismic has been conducted in the permit area in 2004 and 2017.
In 2010, Pangean Resources compiled a report from the review of prior seismic and concluded that undiscovered gross prospective recoverable gas resources within the PEP 11 area were estimated at 5.7TCF at the best estimate level.
BPH has previously said PEP 11 represented a “unique opportunity to explore a frontier Permo-Triassic basin complex containing mature source rocks and active petroleum systems, adjacent to Australia’s most strategic gas market”.