StatoilHydro has added about 7bn barrels of oil equivalent to its resource base in the past two years, even though its reported proved reserves have been shrinking, Norway’s national oil company said as it reported a fall in profit for 2008.

Helge Lund, Statoil chief executive, said the company now had a base of more than 20bn barrels equivalent of oil and gas that it could develop profitably, following deals such as the partnership with Chesapeake Energy, the US gas producer, and the planned Shtokman joint venture off the north coast of Russia with Gazprom and Total.