StatoilHydro, Norway’s national oil company, has made its first move into “unconventional” gas, with a $3.4bn deal to take a stake in assets owned by Chesapeake Energy, the Oklahoma-based gas company.

Statoil called the deal a “step change” in its US gas market position, that would give it access to up to 3bn barrels of oil equivalent of resources and 200,000 boe per day of production after 2020. Analysts had warned that Statoil had a weaker long-term growth outlook than many of its leading rivals.