AIM-listed Valiant said it had passed a key milestone by starting production from the Causeway field in the northern North Sea, in what chief executive Peter Buchanan called a "compressed time-frame".
Causeway is the first producing asset that Valiant has operated for itself.
However, Valiant said Causeway had been producing at lower than expected rates following an unexpectedly long clean-up, due to the long horizontal nature of the well.
The company said: "Due to start-up delays and production performance to date at Causeway, Valiant's production in 2012 is anticipated to average around 6500 barrels of oil per day [bopd]."
In its interim results announcement in September Valiant said it expected production to average 7000 to 8500 bopd in 2012.
The company launched a strategic review which it said would consider options ranging from stand-alone organic growth alternatives to a sale of the business.
Separately, analysts at Jefferies International said Ithaca Energy's third quarter results showed it is on track to meet a forecast for 5000 barrels oil equivalent per day production in 2012.