Roc, whose managing director John Doran previously described the drilling campaign as the last “roll of the dice” in the offshore Perth Basin, said the discovery needed further evaluation to determine its size and whether or not an associated oil leg is present.
Preliminary indications suggested the well intersected 35m of gas-saturated sands, implying that the structure could contain between 60 and 90 billion cubic feet of gas in-place. But the well data suggested that if an oil leg existed, it was likely to be small.
Last week, Australian Worldwide Exploration managing director Bruce Phillips told journalists on the sidelines of the APPEA conference in Adelaide that if the discovery had been oil, it would have been a commercial development.
“If it’s gas, the dice have probably come up snake eyes,” he said.
The gas sand was encountered at the top of the objective section at a depth of 1986m, interpreted as being equivalent to the Dongara Sandstone.
Underlying the gas sand are 232m of shales interbedded with generally tight sands, with gas indications down to a depth of 2065m.
Below this shale-sand sequence, there are several water-bearing sands near total depth.
“An obvious gas-water contact was not seen in the well and further evaluation is required to determine how much of the structure, which has a vertical relief of more than 100m, is gas-filled,” Roc said.
Looking ahead, Roc said the Premier Wilcraft rig will move 80km north to the Perserverance-1 wellsite in WA-325-P where drilling is expected to start by the end of the week.
Participating interests in WA-325-P are Roc (37.5%), Apache Northwest (37.5%), Arc (20%) and Wandoo Petroleum (5%).
Interests in WA-286-P are Roc (37.5%), AWE Oil (27.5%), Wandoo (24%), Arc (6%) and CIECO Exploration and Production (5%).
