The new four-year contracts covering 18 fixed platforms on Norway's continental shelf were part of Statoil's efforts to increase cooperation between various service providers to further boost drilling efficiency, a spokesman said.

"We are also in the market to sign new contracts with providers of oil services to create integrated drilling services as we have done at Johan Sverdrup and Mariner fields," the spokesman added.

Out of 18 drilling contracts announced on Tuesday, Norway's Archer won the most, 12 contracts, sending its shares up 14 by 1230 GMT.

The company estimated firm contract value at more than 6 billion crowns, while it could reach $15 million if Statoil decides to exercise the options.

While Archer will continue to provide platform drilling services at eight installations, it has also won contracts at Grane and Gulfaks A, B and C platforms, taking over from Odfjell Drilling and KCA Deutag respectively.