The historic flow test has excited the JV and Energy News understands that while Quadrant (80% and operator) and partner Carnarvon Petroleum (20%) are yet to decide on a course of action, there are serious discussions about going to drill the Phoenix South-2 in the hopes of flow-testing the Barret Sandstone discovery and the deeper Caley Formation.

The partners could use the same Ocean Monarch rig, pending JV and regulatory approved.

Carnarvon revealed this morning that the gusher flowed at 11,500 barrels of oil equivalent per day on test dispelling any remaining doubts about the potential of the Bedout Sub-basin.

Individual rates were 51.2 million cubic feet per day and 2943bcpd, with the condensate ratio at the higher end of expectations.

The test was constrained by the 1.5-inch choke, meaning the maximum flow rate is yet to be measured.

The flow rates and reservoir pressure conditions were even better than Carnarvon expected, and the upper 35m of the Caley Formation flowed strongly without intervention over five days.

The condensate to gas ratio achieved during the maximum flow rate was 57.5bbl/MMcf.

Testing operations were undertaken at controlled flow rates to enable the monitoring of the field including reservoir pressures, gas and condensate ratios and the presence of other substances such as CO2, H2S, water and sand.

There was little in the way of contaminants in the flow.

The average permeability was assessed at 130 millidarcies, which was much higher than pre-drill expectations, and has resulted in a reassessment of the quality of the Caley reservoir at different depths in the basin.

Earlier estimates had suggested a permeabilites of 100-350mD across three discrete hydrocarbon columns from 4380m over a gross 40m. The lower Caley sands were water-wet.

"Our drilling results to date in the Bedout Sub-basin have been extraordinary. Carnarvon and its partner and operator, Quadrant have made substantial progress in this new oil and gas province since exploration began in earnest in 2014," Carnarvon managing director Adrian Cook said in a statement this morning.

"The Roc-2 well has provided us with a significant amount of valuable new information, and the flow test result very clearly and unequivocally demonstrates the capability of these hydrocarbons to flow from quality reservoir within the basin.

"We are very happy with the Roc-2 well flow test results which are at rates that are significant in our industry."

He said the Bedout Sub-basin must now be regarded was Australia's most promising new petroleum province, with the potential for significant hydrocarbon volumes to exist.

It is now likely the Roc field, and the earlier Phoenix South discovery will form a hub for a commercial development within WA-437-P.

Cook said the results suggested a development well would slow in excess of 100MMcfpd, which was equivalent to around 10% of the entire domestic gas demand in Western Australia.

The domestic gas market has always been a focus for Quadrant and Carnarvon.

Quadrant CEO Brett Darley said the successful test result highlights the prospectivity of the Bedout Sub-basin.

"Since farming into the area in 2012, the Quadrant-led joint venture has achieved a 100% success rate in three exploration wells - Phoenix South-1, Roc-1 and now Roc-2.

"These results show significant potential in this largely unexplored area situated in relatively shallow water."

"The Roc-2 result provides Quadrant the opportunity to evaluate a range of development options given the close proximity to major resource projects.

He added that the private equity-backed company would take a measured approach.

Previously Carnarvon said Roc-1 had defined gross 3C resources of 372 billion cubic feet and 18 million barrels of condensate with similar potential of 328Bcf and 16MMbbl in Roc-2 with an estimated minimum economic field size of around 325Bcf and 17MMbbl.

Roc-2 was drilled 6km east of Roc-1 about 65m updip on the structure.

The partners are planning to drill up to seven appraisal wells around Roc and Phoenix South over the next five years and up to three exploration wells on high-graded prospects.

Carnarvon shares soared 32% to 13.5 cents.