Another week, another swing in Libyan crude output, this time downwards. Recent attacks on, and disruptions to, oil infrastructure suggests that anyone who thought recent gains were here to stay was kidding themselves.

The rollercoaster ride of Libya’s crude oil production took a sharp dip in late March with the closure of the Repsol-operated Sharara fields (NC-115 and NC-186), the country’s largest oil producing concession, and the Wafa wet gas field in the Ghadames basin near...