Here's what energy analysts are most worried about

Brent traded at around $ 71.75 on Thursday afternoon, up around 0.2%, while WTI stood at $ 63.94, around 0.3% higher.

"I want to say that I am most concerned about what role US sanctions will play against Iran … It is the most important issue on the supply side and, of course, an incredibly complicated one," Cailin Birch, global economist at The Economist Intelligence Unit, said. (EIU), CNBC by phone.

The unpredictability of US foreign policy means there is a "big risk", the Trump administration will remove removals against Iran next month, Birch said. On May 2, President Donald Trump must decide to extend exemptions that allow several countries to import oil from Iran, which is under extensive US economic sanctions.

While the Trump administration has a "maximum pressure" policy against Iran, the president says he issued exemptions to eight countries in November to prevent oil prices from rising. The exceptions are also seen as a way to deal with relationships with foreign countries, most of which oppose Trump's Iran policies.

It is certain that analysts doubt that Trump will refuse to extend the waivers, even though the administration services repeatedly call on the administration's goal of running Iran's oil exports to zero.