Berlin - German oil and gas giant Wintershall said on Friday it was expanding its production and reserves in the North Sea after buying shares from Norway's Statoil for $1.25bn.
The deal covers oil and gas fields, a pipeline project and exploration licences and is effective retroactively to January 1, Wintershall's parent company BASF said.
It represents about 170 million barrels of oil equivalent, it said in a statement.
The BASF subsidiary is very involved in Russia via its close cooperation with Russian state gas giant Gazprom and a co-enterprise with Russia's Lukoil oil company.
"We believe in the potential of the Norwegian continental shelf and clearly focus on our goal, we want to become one of the leading oil and gas companies in Norway," said Rainer Seele, chairman of the board of Wintershall.
"With domestic production in Europe we are strengthening the European supply security," he added.
Germany receives about a third of its gas provision from Russia and has long sought to diversify its supply sources, especially from Norway.
The crisis in Ukraine and tensions with Moscow have strengthened its aim.