Though it remains one of the larger prospects in the North Sea, appraisal data of the Johan Sverdrup field yielded no change in reserve estimates, Oslo said.

The Norwegian Petroleum Directorate reviewed data from an appraisal well on the Johan Sverdrup oil field in the central Norwegian waters of the North Sea.

"Based on preliminary calculations, the operator's resource estimate for the field will not be changed," the NPD said. "The licensees will assess the result of the well as regards a possible future development."

At peak capacity, Johan Sverdrup should account for up to 25 percent of total Norwegian petroleum production. Preliminary data for November, the last full month for which data are available, show an average production of 2.15 million barrels of oil, natural gas liquid and an ultra-light product called condensate, which is about 2 percent higher than figures from October.

Norway is one of Europe's main suppliers of oil and natural gas outside of Russia. An audit of the development and production plans for Johan Svedrup found no major issues with the pipeline infrastructure associated with the field.

Contracts worth more than $5.7 billion have been awarded for the project so far. The NPD said the appraisal well was drilled by the Deepsea Atlantic drilling facility, which moves on to drilling development wells for Johan Sverdrup.