Even without these geopolitical concerns, OPEC must face the “million barrel question” if it ever hopes to rebalance the global oil market.

U.S. oil production increased by 88,000 barrels per day (bpd), or more than 1 percent, to 9.34 million bpd, according to data from the U.S. Energy Information Administration. Meanwhile, OPEC’s output rose by 220,000 bpd to 32.49 million bpd in June, according to the S&P Global Platts survey published on Thursday.

However, U.S. crude oil stockpiles did fall sharply by 6.3 million barrels in the week to June 30. Whether or not stockpiles will fall faster in the coming months is the “million barrel question” according to Wang, but he thinks a rebalance by 2018 is unlikely.

“U.S. production is already half a million barrels above where it was when this production cut deal from OPEC started. You’ve got Libya and Nigeria, they’re militancy seems to be calming there now,” he said.

“Their production is up about 400,000 bpd combined above where it was from October levels. So you combine U.S. with Libya and Nigeria, that’s almost a million barrels per day, undoing more than half of this combined 1.8 million bpd OPEC and non-OPEC production cut.”