China’s voracious appetite for natural gas has sparked a wave of deals with US exporters of the fuel, strengthening energy trade between the world’s two biggest economies even as their relationship grows more fraught.

The latest sales were announced on Monday when Venture Global LNG, a company building a pair of liquefied natural gas export plants in Louisiana, said it had agreed two contracts to ship 3.5m tonnes a year of the fuel to state-owned China National Offshore Oil Corporation, the country’s biggest LNG importer.

The Cnooc deals bring to seven the number of big contracts signed between US exporters and Chinese customers since October. Some of the contracts last decades. China is poised to surpass Japan as the world’s largest LNG buyer this year, analysts say, while the US will leapfrog Australia and Qatar in LNG export capacity next year, according to its Energy Information Administration.