Carnarvon said this morning the 12-1/4" hole had now been drilled with casing set and cemented in place, and that the 8-1/2" hold had been drilled to the coring point.

Currently the joint venture is preparing to core the Caley and Baxter members. Both Caley and Baxter proved to be oil bearing intervals in the initial Dorado-1 discovery well last year.

Operator Santos will acquire around 200 metres of whole bore core across the Caley and Baxter before continuing drilling operations and logging while drilling to the total depth of 4,500m.

Once the well reaches total depth wireline logging tools will be used across all reservoirs including the Crespin and Milne members.

The Dorado-2 appraisal well is roughly 2.2km from the Dorado-1 discovery well within the WA-437-P permit.

The well is being drilled with the Noble Tom Prosser and is the first appraisal well since Dorado-1 struck 171 metres of net oil pay, sending Carnarvon's share price rocketing.

The discovery came just after Santos' unexpected huge gas find at Corvus-2, which consultancy Wood Mackenzie suggested would be the largest gas discovery in the Carnarvon Basin since the Satyr-4 exploration well drilled by Chevron in 2009.

Once drilling operations at Dorado-2 are completed the rig will be mobilised to Roc South-1 and then Dorado-3.

Carnarvon Petroleum was down slightly this morning at 42.5 cents per share. Santos was trading at $7.29 per share.