Billionaire oilman Harold Hamm told CNBC on Friday that OPEC has been trying for decades through price wars to crush U.S. crude production. "Sometimes they're successful. This time we hope they're not," he said.

The American shale oil boom is viewed by Saudi Arabia as an economic threat, the founder and chief of Continental Resources said in a "Squawk Box" interview. "I think the Saudis have made up their mind they're not going to bear the brunt of a cut, so they force everybody else to do it." As a result, Hamm argued the OPEC cartel—of which the Saudis are the largest producer—is "not very strong at all" nowadays.