BGR:
BGR Annual Energy Report 2016

10 апреля 2017 г. | The German Federal Institute for Geosciences and Natural Resources (Bundesanstalt für Geowissenschaften und Rohstoffe or BGR) report details the available reserves, production levels and exports for all fuels for all main production countries. Russia has the single biggest reserves of any country with around 48 trillion cubic metres of gas reserves.
 
Find the full report [in German] here.