MOSCOW, April 26 - Gazprom has analyzed the possibility of bidding in tenders to produce natural gas from unconventional sources at the Yuzovska and Oleske fields in Ukraine and decided that this would be unwise because the projects are not economically viable, a source close to the Russian gas giant's board of directors told Interfax, citing a report presented to the board on Wednesday.

Management reported to the board on the outlook of projects to produce gas in Russia from alternative sources, including coal seam, shale and green gas.