Edward Morse, the global head of commodities research at Citi Group, gave a bullish outlook for global oil markets, saying that current inventories were at a "constructive" level.

Crude futures have surged in recent months, with Brent and WT both rallying more than 20% since the start of 2019. Morse believes that more upside is in store with supplies being taken off the market in Iran and Venezuela, as well as major oil cartel OPEC.

"I think it's under bought, I think it was oversold ... The market is very constructive, it's fairly tight and we think it's going to be in the $70 range through the second quarter and into the third quarter depending on what happens. And there's a lot of variables between now and then," he told.

One variable is whether the President Donald Trump administration will extend sanctions waivers on eight countries importing Iranian oil and he has until May 2 to decide. Morse believes that the focus for the U.S. will be sanctions and Venezuela and this would likely see "kinder" actions on those importing Iranian oil.