Since Aramco began building the Jazan refinery and associated oil terminal in 2014, the local geopolitical situation has deteriorated sharply, with Riyadh supporting the Yemeni government in its campaign to quell Houthi rebels, whose area of operation is just south of Jazan in northern Yemen.

Houthi militants attacked two Saudi VLCCs in the 20km-wide Bab al-Mandeb straits in late July, temporarily halting Aramco’s Red Sea tanker traffic. While Aramco resumed shipments in early August,...