The attacks on critical oil production facilities in Saudi Arabia over the weekend will effectively wipe out the world’s spare oil capacity, an expert from S&P Global Platts said.

Drone strikes attacked a oil processing facility at Abqaiq and the nearby Khurais oil field on Saturday, knocking out 5.7 million barrels of daily crude production — or 50% of the kingdom’s oil output. That’s more than 5% of global daily oil production.

“This heightens the risk premium, it puts a lot of pressure on the supply side,” said Sarah Cottle, global head of market insight at S&P Global Platts.

“This incident effectively eliminates the world’s spare capacity,” Cottle told CNBC, though she added the longer-term outlook is bullish due to the immediate need to draw down on crude stockpiles.