The company in mid-November announced Blackbird had discovered four oil-bearing intervals in the main Middle Dua sandstone target, two of which have now been tested.

It said the deepest zone test-flowed oil at a sustained rate of 2177 barrels of oil per day and 1.63 million cubic feet of gas per day, through a 44/64-inch choke with a wellhead pressure of 618 psi.

The second zone test-flowed oil at a sustained rate of 3706bopd and 2.49MMcfd of gas, through a 1 inch choke with a wellhead pressure of 544 psi.

Santos said no water was produced during either test. Once the drill stem tests are finished the Blackbird well will be sidetracked to obtain further information from the reservoir.

Santos said the sidetrack would accelerate the appraisal of the field, beginning with resource assessment and reservoir evaluation reports.

“The strong oil flow rates from Blackbird are very encouraging, particularly as this follows on from the successful testing of the Dua discovery,” Managing director John Ellice-Flint said.

The Blackbird discovery is in Block 12E offshore Vietnam, about 21km to the southwest of the Dua discovery announced in June 2006.

Interests in Block 12E are Santos with a 37.5% interest, operator Premier Oil with 37.5% and Delek Energy with 25%.