Drillsearch said Rig PDI-735 had reached the total depth of 1385m, with oil shows being encountered in the Birkhead reservoir unit during drilling.

Wireline logs indicated about 1.5m of net oil pay in the middle Birkhead unit and the well was now being cased and suspended as a future oil producer.

But evaluation of the core sample recovered from the Classic-1 near field exploration (NFE) well, near the northern edge of the Tintaburra block, revealed tight reservoir conditions, which were confirmed by a drill stem test.

That well was therefore plugged and abandoned last weekend and the Rig PDI-724 released to the Endeavour-9 well, which spudded on Tuesday. Current operations were pressure testing the blow-out preventers, before drilling ahead.

Rig PDI-721 was released late last week after casing the new oil production well Chancett-1 and was now drilling the Bilberry-1 NFE well, about 3km northwest of Gimboola West-1.

Interests in the Tintaburra Block are Santos (operator with an 89% stake), Drillsearch Energy (10%) and CPC Energy (1%).