MOSCOW, Oct 25 (Reuters) - Gazprom"s (GAZP.MM) natural gas exports to Europe and Turkey could reach 183 billion cubic meters by the end of the year, the head of the Russian gas giant"s export branch said on Monday, confirming a previous estimate. In comments carried by the company"s magazine, Gazprom Export chief Elena Burmistrova added that the firm had supplied 7.1 billion cubic metres of gas to China in the first nine months of 2021.