The rapid growth of the US as a crude exporter has been much commented on – though no less dramatic for it – less so has been the fact that imports have fallen by much less, despite demand largely staying steady. Exports of NGLs and refined products are also at record levels. Taken together US oil trade hit a record 16.2mn b/d in 2017, the highest figure for any country ever.

US oil output is at record levels. Crude production rose to 9.64mn b/d in October, the highest figure...