The soaring cost of moving oil around the world is making some long-distance crude trades uneconomical, threatening to disrupt flows at a time when fuel markets have never been tighter.

The jump is being driven by a shortage of available supertankers. In some parts of the world, there are barely any of the ships — each the length of three football fields — left for hire. The squeeze is making faraway barrels less attractive and encouraging refiners to snap up supplies closer to home if they can find them.

Moving a cargo from Houston to Asia now adds about $26 a barrel — $52 million a cargo — to the cost of supplying the world’s largest crude-importing region. That’s equal to roughly a quarter of the price of West Texas Intermediate futures. Before the war, shipping typically accounted for only a tiny fraction of the cost.