Oil prices will continue to fall, but don't expect the United States' shale boom to slow down any time soon, noted investor Dennis Gartman told CNBC Friday.
U.S. crude prices tumbled Friday after OPEC decided not to cut production to stem plunging oil prices.
"The fact that OPEC for all intents and purposes is broken apart and is really now a broken cartel only serves to make certain that crude oil prices are still going to fall even further. I think they have a lot farther to go down before this is out of the way," Gartman, editor and publisher of "The Gartman Letter" said in an interview with "Closing Bell."
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U.S. crude's front-month contract closed $7.54, or 10.2 percent, lower at $66.15 per barrel on Friday, its lowest settlement since September 2009.
The front month for benchmark North Sea Brent crude closed $7.54, or 10.2 percent, lower fell about $2 to $70.45, its lowest since July 2010.
While falling prices are not good for oil producers in North Dakota or Texas, it is "unambiguously good" for the American consumer, he added.
That said, he thinks that it will be "quite some period of time" before production of American oil is curtailed.
"It takes so long to bring new product on, to put new pipe in the ground, to put new drills down," Gartman said. "Banks have already lent money on new drilling. You are probably going to have an expansion of crude production here in the United States for at least another six months, maybe nine months."
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After that, he said, there may be a slowing of the increase in production. However, he thinks it will take $50 or $55 crude oil to actually curtail the amount of production in the United States.
"We're going to soon surpass Saudi Arabia, that's something that's going to happen, it's a fact," Gartman said.
—Reuters contributed to this report.