Oil futures fell more than half a dollar on Tuesday given worries rising Iranian output would deepen a global oversupply, offsetting expectations of a drop in U.S. production that had spurred sharp price gains in the previous session. Key oil exporters Saudi Arabia and Russia have proposed to freeze output at January levels, which were near record highs, only if other producers also do the same. But Iran, now free of western sanctions that hurt its crude trade, is seen as unlikely to join, casting doubts over whether the freeze will happen. “Iran’s early post-sanctions marketing appears to be effective with the National Iranian Oil Company indicating that exports have risen by 500,000 barrels per day since sanctions were lifted in mid-January, […]