The national energy regulator in Norway said preliminary results from a North Sea field show a potential increase in estimated recoverable oil reserves.

The National Petroleum Directorate said it was reviewing the preliminary results from an appraisal well drilled by Lundin Petroleum in the Edvard Grieg oil field in the central section of the North Sea.

"Preliminary calculations show that the results from the well may result in an increase of between 6.2 million and 50 million barrels of recoverable oil in this section of the Edvard Grieg field," the regulator said in a statement. "Further work is expected to reduce the uncertainty of this estimate."

Lundin in early August revised its production guidance lower to 32,000 barrels of oil equivalents per day as a result of less than expected output from the Brynhild filed off the coast of Norway and infrastructure delays for its Edvard Grieg rig.

Edvard Grieg was discovered in 2007. The company says first production from the field is expected in late 2015. Peak production is anticipated at 90,000 barrels of oil and 53 million cubic feet of natural gas per day.

Lundin, which has headquarters in Sweden, made an oil discovery in a previously untapped area within the Luno II North prospect in the North Sea field last week. For Norway, the upward revision could support future growth in an economy that depends on oil as a source of revenue.

The Norwegian government said last week its economy, as measured by gross domestic product, was weakened because of the depressed oil market. Crude oil prices are trading below $50 per barrel, putting downward pressure on the economies of exporting nations.