Oil prices have dropped to a four-month low amid booming supply and sluggish demand, but Clem Chambers, CEO of investment web site ADVFN.com, says a rebound is coming.

"There is a massive low on the horizon, and all investors should watch out for it," he writes on Forbes.com. "That opportunity is the coming low in oil. That point might not be next week but it is getting closer by the day."

U.S. crude traded at $45.40 a barrel Wednesday afternoon.

"Unless some new technology takes hydrocarbons out of the picture as dirt cheap energy, oil is always going to be a massively important commodity," Chambers says.

It's safer to invest in dividend-paying oil stocks than in the commodity itself, he notes. Among the stocks he recommends when oil prices bottom are Chevron, Exxon Mobil, Statoil, Royal Dutch Shell and BP.

Chevron has a dividend of 5 percent, Exxon of 3.8 percent, Statoil of 5.4 percent, Royal Dutch Shell of 6.7 percent and BP of 6.6 percent.

David Rubenstein, co-CEO of private equity firm The Carlyle Group also is an oil bull.

"In time (oil) prices will come back, in time demand will catch up with supply, and in time I do believe that carbon-related energy will turn out to be one of the best investments in the world," he told CNBC. "The consumption of energy is something that we need to do to make the world go forward."

U.S. Crude prices reached $106 in June 2014 before dropping 57 percent. Meanwhile, gasoline prices at the pump have slid 25 percent over the last year to $2.63 a gallon, according to AAA.

Rubenstein also agrees with Chambers that oil's drop creates investment opportunities. "We are, in the United States and outside the United States, very active," Chambers said. "I don't want to predict any wide-scale declines in the value of all these (oil) companies, but I do think there will be opportunities to buy things at lower prices."

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