From July 17/ 2017: The U.S. refiner industry has economic reasons to decrease import of Venezuelan heavy crude—Maduro wants everyone to believe the reduced export to the U.S. is a result of his policy moves.
“U.S. oil refiners pare exposure to Venezuelan crude imports”
https://www.reuters.com/article/us-usa-refiners-venezuela-idUSKBN1AC36M
From the Reuters article at post 39:
“U.S. refiners are shifting away from processing heavy crude, lessening the potential impact on their businesses and motorists of any supply disruptions from Venezuela as the Trump administration considers new sanctions on the country.”
“Additional financial or import sanctions that would choke off the country’s access to U.S. dollars for its oil also are being weighed.”
“U.S. imports of Venezuelan crude fell 32 percent in June”
“less supplies coming from Latin American producers and growing supplies of shale oil have improved the economics of running lighter crudes.”
Venezuela is heading toward a cash crisis with its oil revenue - and it is entirely dependent on oil revenue, or credit backed by its oil revenue.