FILE PHOTO: A worker walks past a pump jack on an oil field owned by Bashneft company near the village of Nikolo-Berezovka, northwest from Ufa, Bashkortostan, Russia, January 28, 2015. REUTERS/Sergei Karpukhin
FILE PHOTO: A worker walks past a pump jack on an oil field owned by Bashneft company near the village of Nikolo-Berezovka, northwest from Ufa, Bashkortostan, Russia, January 28, 2015. REUTERS/Sergei Karpukhin