FILE PHOTO: A worker walks past a drilling rig at a well pad of the Rosneft-owned Prirazlomnoye oil field outside the West Siberian city of Nefteyugansk, Russia, August 4, 2016. Picture taken August 4, 2016. REUTERS/Sergei Karpukhin/File Photo
FILE PHOTO: A worker walks past a drilling rig at a well pad of the Rosneft-owned Prirazlomnoye oil field outside the West Siberian city of Nefteyugansk, Russia, August 4, 2016. Picture taken August 4, 2016. REUTERS/Sergei Karpukhin/File Photo