A perfect storm of macroeconomic factors has dragged oil prices lower, but China's stock market slide kicked off this week's 10 percent plunge in crude futures, said Tamar Essner, energy analyst at Nasdaq OMX.
Traders had largely digested progress toward a deal on Iran's nuclear program and Greece's debt standoff, but a nearly 30 percent correction in Chinese stocks caught them unaware, she said Tuesday.
"I don't think the market really anticipated that things were quite as bad as they were in China," she told CNBC's "Squawk on the Street." "That had been a big tool in the arsenal of the oil bulls out there, who had said oil demand had been understated and could really surprise to the upside driven by China. That's now thrown into question."
Oil supplies in the United States and OPEC remain strong and should remain robust for the next two years, she said. At the same time, the hallmarks of the last 15 to 20 years that have supported oil prices—a weak dollar and low interest rates—are on the cusp of reversing.
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Matt Smith, director of commodity research at Clipper Data, said the developments in China have exposed a disconnect between strong gasoline demand there and weak underlying economic data. He said the run-up in Chinese stocks has left investors feeling wealthier, but China's stock market correction stands to dampen demand.
"While we have seen SUV sales up 50 percent through May versus last year, sedan sales up 20 percent, what we're likely to see is a reversal of that gasoline demand growth, and that will only exacerbate the glut in the market potentially," he told CNBC's "Squawk Box."