Oil production fell to 1.24 million barrels per day in the month from 1.50 million in August, primarily due to technical problems at several fields and planned maintenance, the NPD said in a statement, and expectations of production for the rest of the year now looked too optimistic.
"Since the prognosis for the remainder of the year is relatively high, it might be a challenge to meet the oil production target for 2012," NPD forecasting director Jan Bygdevoll said. "Oil production is about 2.0 percent below the cumulative prognosis this year."
Gas sales for Europe's second biggest supplier also fell sharply, coming in at 6.9 billion cubic meters for the month, down from 8.1 billion cubic meters in August.
The NPD said that both Valhall and Hod fields were closed for the entire month while the Yme and Skarv fields, both factored into forecasts, were offline and will not produce in 2012, it said.
Forecasts for October indicate daily production broadly in line with last year's 1.7 million barrel per day output, NPD data showed.