Saudi Arabia's Oil Minister Khalid al-Falih declared the cycle of low crude prices is nearing an end as the oil market strengthens in recent weeks.

"Market fundamentals, in terms of supply and demand, have begun to improve," Falih stated on Sunday at a press conference with Russian Energy Minister Alexander Novak, adding: "We are optimistic that oil prices will continue to improve in the future."

Novak was meeting with OPEC ministers to discuss closer cooperation between Russia and OPEC to support the market.

Last week WTI Crude was trading at nearly $52/barrel, a 15-month high. It has slipped somewhat since, to about $50.50, after comments from Iraq's Oil Minister Jabar Ali al-Luaibi indicating his country wanted to be exempt from any output cuts that OPEC might impose, saying Iraq needed the revenue to fight the Islamic State.

Energy trader Mark Fisher is advising investors to buy crude oil and natural gas on dips. "In my opinion, the most likely course is for the market to gradually establish a new base someplace in the $55 to $65 range barring some kind of geopolitical problem," he told CNBC.

"It used to be that in natgas, every time the market rallied you could just close your eyes and sell it. I think those days are long over. I think now the time has come that you can basically buy every dip," he said.