Echinda-1 confirmed the column from wireline pressure data across the Paleocene and Maastrichtian-aged reservoir intervals, while fluid samples recovered measure a 39.5-degree API oil gravity.

The company is now planning for a well test of the 75m-thick Paleocene reservoir section, which has 50m of net pay with porosity assessed at 25%.

The Maastrichtian reservoir sections will be tested as part of a follow up drilling program.

The deeper Maastrichtian reservoir interval has a gross thickness of 113m (50m net) with an average porosity of 21%. A pressure defined oil gradient shows the Maastrichtian formation to have the same oil pressure gradient and gas-oil ratio as the Paleocene reservoir and the oil recovered is also very similar to the recovered Paleocene samples.

A deeper Maastrichtian oil column was also intersected in a separate 7m sand with an average 23% porosity. The interpretation of oil is supported by natural shows and a pressure-defined oil gradient.

The Echidna discovery represents another significant achievement for Karoon substantiating the validity of the salt flank play, managing director Bob Hosking said.

"Echidna adds incremental resource to Karoon's discovered Kangaroo oil field which further supports Karoon's ambitions to develop an integrated production hub in the Santos Basin," he said.

The Echidna-1 exploration well is located in Block S-M-1102, on the east side of the Emu salt diaper complex, and tested a similar salt flank play to that first proven by Kangaroo-1 and later confirmed by Kangaroo-2.

A decision with respect to the second well option will be made in the coming weeks.

Karoon is also planning further appraisal drilling to help with ongoing pre-FEED studies to support the development.

Karoon holds a 65% operated interest in S-M-1102 with Pacific Rubiales Energy Corp (35%).