SINGAPORE, Oct 13 (Reuters) - China imported 41.05 million tonnes of crude oil in September, or about 9.99 million barrels day, customs data showed on Wednesday. Natural gas imports were 10.62 million tonnes, the highest since January. 1 tonne of crude oil=7.3 barrels Reporting by Chen Aizhu; Editing by Christian Schmollinger Our Standards: The Thomson Reuters Trust Principles.