The premium Brent crude commands over Nymex WTI is set to widen back toward record highs seen last year, as increased oil production in North Dakota and stock builds at the U.S. benchmark's delivery point of Cushing, Okla. pressure WTI, Seth Kleinman, head of energy strategy at Citi said Thursday.

"The spread is heading toward $20 again and it needs to get there because all of the esoteric ways of getting oil out of Cushing don't make sense when the spread is under $10," Kleinman told the ETF Securities investment conference in London.

Meanwhile, Brent is very well supported by geopolitical risks to supply, he said.

Eoin Treacy's view A slow return to economic growth and a surge in domestic supply, not least from North Dakota's shale oil, is contributing to abundant supplies of crude oil in the USA. Concurrently, geopolitical risks in Africa and the Middle East have added a risk premium to Brent Crude prices.

Brent crude continues to trade in backwardation and remains stable above the 200-day MA. A sustained move above $115 would likely reaffirm medium-term demand dominance.

WTI crude is trading in contango. It has failed to hold a move above $100 since November and is currently pulling back from that area. A sustained move above $101.50 would be needed to question potential for some additional lower to lateral ranging.

As a result, the spread between the two contracts has begun to widen once more. It hit an historic peak near $27 in August and fell below $8 by late December. The spread has since held a progression of higher lows and rallied impressively this week. A sustained move below $10 would now be required to check potential for continued outperformance by Brent crude.