Qatar’s decision to double its gas development plans from the giant North Field means that although its position as the world’s leading LNG exporter is under imminent threat, it should re-assert its dominance in the mid-2020s, even if global LNG supplies continue to grow into the next decade.

As the Saudi-led blockade against it shows no sign of easing, Qatar’s move showcases its potential to generate new, longer-term revenue in spite of low hydrocarbon prices and fierce...