The United States imposed sanctions on Iran this month and asked international consumers not to buy their oil, and Iranian raw exports have fallen sharply in recent months.
But other oil producers have more than compensated for the lost Iranian oil, and most analysts now see a significant supply surplus with warehousing, which pushes prices.
OPEC is expected to start trim production soon and fear a repeat of the 2014 price range. This could trigger a rapid price increase, says some analysts, especially if production falls further in Venezuela and Libya.
"We are likely to have at least 1 million barrels per day (bpd) less of (Iranian) raw exports," said Harry Tchilinguirian, Global Commander of Commodity Market Strategy at BNP Paribas, to the Reuters Global Oil Forum.
Tchilinguirian said he would not be surprised if Brent recovered at $ 80 a barrel this year.