Oil makes shaky gains on optimism over non-OPEC output cuts

By Libby George LONDON (Reuters) - Oil prices were edging higher for a second session on Friday on hopes that non-OPEC producers meeting in Vienna would agree to cut output to bolster the group's own agreement to limit production. On Saturday, oil ministers from OPEC countries will meet non-OPEC producers in Vienna to seek help in curbing a global glut. Russia has said it would cut 300,000 barrels per day, meaning other non-OPEC producers combined would need to pledge the same amount to lower ou