An audit of elements of the early operations tied to infrastructure at the Johan Sverdrup oil field offshore Norway uncovered few issues, a regulator said.

The Petroleum Safety Authority of Norway issued the preliminary results of an October audit of Statoil's procurement processes and the fabrication of parts of the infrastructure that will be used for production from the Johan Sverdrup field.

"No non-conformities were detected during this audit," the PSA said in a statement.

At around the time of the audit, the PSA gave Statoil permission to proceed with new drilling in the North Sea field.

Developed over a series of phases, operator Statoil said the Johan Sverdrup oil field should account for up to 25 percent of total Norwegian petroleum production once at peak capacity.

By its latest estimate, Statoil said the project will be competitive as long as crude oil prices hold above the $30 per barrel mark.

In terms of production, Statoil said efficiency measures in part meant more was expected from the field than initially thought. Drilling for the four survey wells started Nov. 1 and will last about four months.

Statoil and its partners at Johan Sverdrup, Maersk Oil and Lundin Petroleum, in early 2014 outlined the development plan for the field using multiple phases. The field will be developed using four fixed facilities and some production is slated to begin in late 2019.