"This rate was deliberately constrained to optimise data gathering and sampling," Otto said in a statement.

"The expected initial rate from Galoc-4 when the field comes on full production is expected to be higher than this test rate."

Nido described the Galoc-4 flows as "tremendous".

"Nido estimates that the combined productivity of the two wells is at the high end of the expected range," deputy managing director Joanne Williams said.

"This will be confirmed following an update to the reserves certification which Gaffney, Cline and Associates will perform on Nido's behalf."

The Galoc-4 result follows last week's testing of the Galoc-3 development well, which flowed at up to 5397 bopd.

Both wells are now ready for connection to the Rubicon Intrepid floating, production, storage and offloading vessel when it arrives in March for first commercial oil production in May.

Otto said it was "extremely pleased" with the results from Galoc-3 and Galoc-4.

"Analysis of the clean-up flow from the Galoc-4 well has shown it is the best of the two development wells and both are at the high end of the pre-drill expectations," it said.

Otto has received its stake in the project via the acquisition of a 31.38% shareholding in Galoc Production Company, which is operator and holds a 58.29% stake in the development in offshore Palawan Basin service contract SC14C.

Other members of the consortium are Nido Petroleum, with 23%, Alcorn Gold Resources, Forum Energy, Oriental Petroleum, PetroEnergy Resources and Philodrill.